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Math Mammoth Curriculum Homeschool
Build a Strong Foundation in Math
Your Child will TRULY Understand Math

Free Video Lessons

1st Grade Math Video Lessons
Chapter 1: Addition of single-digit numbers

Kindergarten addition lesson: learn to write sums with + and =

In this video lesson children learn the meaning of the symbols + and = (plus and equals) and write simple addition sentences using them. It is most suitable for kindergarten math but can be used in early 1st grade also.

I also include sums with zero as that is an important concept (for example, 0 + 2 and 0 + 0). The lesson is easy and straightforward and lets kids think before I say or write the answers. Mathy my mascot mammoth draws surprise pictures for one problem. :)

Addition with missing numbers - 1st grade/Kindergarten math lesson

An introduction or beginner lesson on addition problems with a missing number - also called "missing addend problems".

For example, we consider the problem 1 + ___ = 4, but since children tend to confuse this with 1 + 4, I start out by placing the TOTAL at the top of the visual model (dots on die faces). So, it reads kind of like:

4 1 + __

This positioning is to help children understand better the concept, and not to get a misconception that it means 1 + 4.

From that we then transition to the regular way to write the addition horizontally, such as ___ + 2 = 3.

Lastly in the lesson we even drop the visual model of dots — by this time the children can probably think the answers and get them correct!

This lesson is meant for early 1st grade or kindergarten. I use very small numbers (from 0 to 5) so that even young children can understand the idea.

Learn addition facts within 10 - drill video lessons

The videos below present an organized and logical method for children to learn their addition facts within 10 using PATTERNS that arise from the number system itself. Children LOVE patterns, and patterns are the essence of math — mathematics has even been defined as the "science of patterns".

In this method, we study sums with 5, sums with 6, sums with 7, and so on until sums with 10 (also called "number bonds"). These sums or number bonds are not studied in random order, but grouped by the SUM, or the "answer". For example:

Math Mammoth Curriculum Homeschool

Notice that each set of sums (1) has the same SUM or same answer; (2) the first addends (numbers to add) go from 0 onward in order, and (3) the second addends go in descending order.

Each lesson first presents the facts to be studied organized in a "table". Then I (or sometimes Mathy my mascot) drill them with the viewers, pausing for enough time to let children say their answers.

This approach will help the child to tie in the addition facts with a context to better understand the facts on a conceptual level, instead of merely memorizing them at random.

You will also find these lessons in paper (or electronic book) format in Math Mammoth Addition 1 (short workbook) and in Math Mammoth Grade 1 complete curriculum.

What about subtraction facts? Math Mammoth curriculum practices subtraction facts in the context of fact families. They are presented in my book Math Mammoth Subtraction 1 (short workbook) and in the abovementioned complete curriculum.

Number line addition

I and Mathy my mascot solve number line addition problems (and Mathy jumps on the number line!). Initially we use little jumps that are one unit long, and then we on go to use arrows that are longer and match the numbers to be added.

These are easy single-digit addition problems suitable for kindergarten and early 1st grade.

We also solve two word problems - one is an addition word problem and the other is a missing number problem. Lastly, children get to see simple patterns in addition.

Addition of three numbers - fun math lesson for 1st grade

In this 1st grade lesson, I show children how to add three numbers. I explain that you can add them in any order and get the same answer. We also add (and Mathy my mascot jumps!) on the number line.

Near the end, the lesson contains some review problems: first, doubles, and then a simple addition table that many children like to fill in as a fun puzzle. Pause the video to let your child think on the problems. This lesson is meant for first grade math.

Compare numbers and sums using symbols <, >, and =

In this 1st grade lesson, Mathy my mascot and I compare numbers and sums using the "alligator mouth" symbols < and > and the equals sign =.

For example, we compare 7 and 2 + 4. Since the sum 2 + 4 is 6, and 7 is greater than 6, we write 7 > 2 + 4.

Of course children must have learned how to compare numbers less than 10 (for example, comparing 6 and 9) before watching this lesson, but it is a natural extension of simple comparisons and helps children learn the concepts behind the inequality signs -- and also the correct way to use the equals sign.

In the end, Mathy has a silly word problem for us to solve! But, I turn it around and ask the kids: What COULD we ask in this situation?

Chapter 2: Subtraction and related concepts

Subtraction and addition in the same picture — there is a CONNECTION between the two

A lesson for 1st grade math... learn the CONNECTION between addition and subtraction in an easy way! Just look at the PICTURE. We have a picture with, say, 4 raspberries and 3 blueberries. From that, we can write an addition of course — but we can ALSO write a subtraction! We just make the one part (4) or the other (3) "go away".

In the latter part of this lesson, we also look at "alligator mouth" problems — or, like Mathy likes to call them, "mammoth mouth" problems. We compare simple expressions, such as 2 + 2 and 5 − 1, and figure which one is greater than the other.

Then we solve some simple subtractions. Lastly, I give a challenging word problem concerning Ted's cars, and we solve it by DRAWING.

Two subtractions from one addition

In preparing students for the concept of fact families, this lesson shows how we can get two different subtractions from one addition, using visual models. It also ties in with the connection between addition and subtraction.

For example, if we have 4 and 2 marbles, it makes a total of 6. From that 6, we can either subtract the 4, leaving 2 — or we can take away the 2, leaving 4. The picture is a very powerful aid in helping children understand this!

We also solve some simple true/false statements and word problems in the latter part of the lesson.

Fact Families - addition & subtraction - video lesson for 1st grade math

In this 1st grade math lesson, we write FACT FAMILIES using small numbers. A "fact family" consists of two additions and two subtractions that use the same three numbers. It's the same concept as NUMBER BONDS. For example, 2 + 6 = 8, 6 + 2 = 8, 8 − 2 = 6, and 8 − 6 = 2 makes up a fact family (two addition facts plus two subtraction facts).

If you're given just ONE of those facts (either addition or subtraction), you can write the entire fact family, and that is what we practice in the middle part of the lesson.

Lastly, we solve two word problems that involve bicycle and tricycle wheels — DRAWING the problem helps a lot here!

The concept of "how many more" - video lesson for 1st grade math

I show with visual models what the idea of "how many more" actually means. For example, if Jack has 3 berries and Bill has 7, we draw those berries, then match the three that both of them have, and then we can count how many more Bill has than Jack.

In this lesson, I don't yet present subtraction as a way to solve "how many more" problems (I feel it is better to delay that). Instead, we practice this concept throughout the lesson by DRAWING items.

Lastly, we solve several word problems about toy cars, and once again draw items to help us.

This lesson is meant for initial teaching of the concept of "how many more" in 1st grade math.

"How many more" problems and difference - video lesson for 1st grade math

I explain the concept of DIFFERENCE as how far apart two numbers are on a number line. Then we tie that in with addition, specifically: addition sentences in the form of "how many more?"

An example: To find the difference between 5 and 9, think of the addition 5 + ___ = 9, or "5 plus how many more makes 9?"

Then we find differences between given numbers by making "hops" on the number line. Mathy my mascot hops too! We also write addition sentences to match these hops and differences.

Lastly we look at items that two people have, and how many more one has than the other (a common theme in word problems).

Chapter 3: Place value

Naming and writing two-digit numbers

A simple lesson for 1st grade where we practice place value with 2-digit numbers (tens and ones), plus naming and writing these numbers.

For example, the number 2 tens 5 ones is written as 25 and is called "twenty-five".

"Teen" numbers — thirteen through nineteen

I explain how the word "teen" in the "teen numbers" actually refers to ten. For example, fourteen means "four-ten", or ten plus four. Thinking of it that way, these "teen numbers" (thirteen, fourteen, fifteen, etc.) tie in neatly with place value.

We also practice with a hundred-chart, finding numbers ending in 5, whole tens, numbers in the 40s, and such.

Add and subtract whole tens

In this lesson we add and subtract whole tens, such as 50 + 40 or 90 − 70, using mental math. (These types of numbers are also called multiples of ten in the higher grade levels; I just don't use that terminology when talking with 1st grade students.)

First, students can use pictures (base ten blocks) to add and subtract, but I'm sure they soon notice the SHORTCUT: you can simply work with the number of tens the same way you add or subtract single-digit numbers. That way, 50 + 40 becomes 5 tens + 4 tens, which is 9 tens.

Lastly, Mathy gives us a challenging addition problem to solve... making TENS helps a lot!

Bar graphs — 1st grade lesson

Mathy my mascot has given us two bar graphs to study. The first one lists Mathy's socks by color. The second one tells us how many math problems Mathy solved on various ways. I have fun figuring out answers to various questions concerning the graphs — and you can too!

Chapter 4: Addition & subtraction facts

Addition and subtraction facts with 6, 7, 8 & 9 - fact families approach (1st grade math)

I show all the fact families with the sum of 6, 7, 8 & 9, organized into a table. Seeing the structure and the patterns in this manner helps develop number sense and helps children in the memorization work, also.

Then we drill the facts for a bit. The lesson also includes an exercise where we draw lines connecting facts from the same fact family, and a word problem.

Subtract many numbers - video lessons for 1st grade math

In the video below, I first solve two subtraction problems with the help of visuals (strawberries!). Then I explain two different ways to subtract two numbers: subtract them one at a time -- or add the numbers to be subtracted, and subtract the sum.

Chapter 5: Time

Learn to tell time — whole and half hours

These video lessons help children learn to tell time on an analog clock, focusing on the whole hours and half hours.

In the first lesson, we ONLY use the hour hand — to make it easy for young students (kindergarten/1st grade) to learn to tell time. In this lesson, we only deal with whole and half hours, such as 4 o'clock and half past 7.

In the second video, Mathy my mascot and I solve simple exercises concerning whole and half hours on an analog clock. We still don't use the minute hand. We tell time using "o'clock" and "half past" — and even figure out what time it is half an hour after the given time.

Telling time — whole and half hours — with the minute hand

In the previous lesson, children learned to tell time (whole and half hours) with an analog clock that didn't have the minute hand but only had the hour hand. In this lesson, I now introduce the minute hand.

I show how the minute hand travels one full round (60 minutes) while the hour hand goes from one hour to the next, such as from 4 to 5 on the clock face. This full round is 60 minutes, and so half an hour is 30 minutes.

So, this is why a time such as "half past 5" can also be stated as 5:30 — using hours AND minutes.

Next, we practice telling time (whole hours and half hours) in these two ways: either using the "o'clock" / "half past", or stating the hours and minutes.

We also figure out what time it will be half an hour later.

AM and PM (morning and afternoon) hours

A simple lesson for 1st grade math, helping children learn morning hours (AM), noon, and afternoon hours (PM). I use a timeline or a number line with hours to show exactly which hours of the day are AM, and which are PM.

Basically, AM comes from "ante meridiem", which literally means "before noon". And PM comes from "post meridiem", meaning "after noon".

We also talk about the common times to sleep and eat various meals using the time line - even Mathy my mascot mammoth chimes in about that! :)

In the 2nd part, Mathy my mascot draws on clock faces the times when he gets up, eats lunch, and goes to bed. Then I write those times under the clocks. We need to use AM or PM, each time.

Chapter 6: Shapes and Measuring

Basic shapes — circles, triangles, squares, and quadrilaterals

In this easy 1st grade geometry lesson, we study these BASIC SHAPES: circles, triangles, squares, and quadrilateral. The emphasis is on how many sides/corners they each have. We also study the meaning of the difficult word "quadrilateral" as a four-sided shape.

Then, we divide existing shapes into new ones and check what we get.

Halves and quarters - and thirds also!

In this easy fraction lesson for 1st grade, we don't yet study the fraction notation, but just learn the concepts related to halves, thirds, and fourths (quarters). I show these by coloring in the corresponding parts.

We also compare two given fractions by coloring. It's basically pretty fun! Fractions don't need to be difficult, scary "monsters" at all!

Measuring length — whole centimeters

In this lesson, we learn to measure lines and things (marker pen, baby block, Mathy my mammoth mascot) with a centimeter-ruler, in whole centimeters, to keep it simple for 1st grade students.

Then I also show how to DRAW lines that measure a certain length. That is actually pretty easy, as long as you remember to hold down the ruler with your other hand. :)

Chapter 7: Addition and subtraction of two-digit numbers

Add a 2-digit number and a single-digit number mentally - no regrouping

In this lesson for 1st grade, I show with a visual model how EASY it is to add sums such as 23 + 6 or 54 + 3 mentally.

You simply add the ones, and the tens do not change. To solve 23 + 6, add 3 + 6 = 9, and the answer is 29. Children will easily get this idea when shown a visual model.

We also add numbers "in boxes" — in other words, by writing one number under the other, or adding in columns.

The lesson also includes an initially silly word problem (by Mathy my mascot mammoth), and some comparisons that require a bit of algebraic thinking.

Note that the sums in this lesson do not require regrouping (carrying) — we study that process in another lesson.

Add and subtract 2-digit numbers without regrouping

In this 1st grade lesson, we add and subtract two-digit numbers WITHOUT regrouping (no carrying nor borrowing). First we do that with a help of a visual model, and then "in boxes", or by writing one number under the other, and then adding/subtracting the ones and the tens.

We also solve several word problems. The first one is challenging, but the visual model (boxes for tens and dots for ones) helps us to solve it easily.

"Make ten" strategy for addition (1st grade math)

A lesson about the concept in addition that I've termed "going over to the next ten". We have either two single-digit numbers or one two-digit and one single-digit number to add. Essentially, you first make ten, and then check what you have "left over".

This strategy promotes number sense (very important for elementary grades) and conceptual understanding.

A mental math trick — addition with nine and eight

This neat and easy "trick" allows you to add 9 or 8 to any number with ease!

For example, to solve 9 + 7, imagine that 9 wants to be 10, so it gets "one" from the seven, leaving seven to become only six. So the addition 9 + 7 is changed to the sum 10 + 6 which is super easy to solve.

We can also use a similar strategy in sums with 8. For example to solve 8 + 5, imagine that 8 wants to be 10, so it gets two from the 5, which then becomes only 3. So the sum 8 + 5 becomes 10 + 3, which is an easy sum to solve.

First and second graders can use these mental math techniques to help their load of memorization of addition facts.

This same "trick" or thought pattern also works with two-digit numbers ending in 9, three-digit numbers ending in 99, and so on.

Pictographs - 1st grade video lesson

First we look at a simple pictograph (pictogram) where one circle represents one bucket of blueberries picked. We solve several word problems concerning differences and totals.

In the second pictograph, one car picture represents FIVE toy cars. This time, I ask the children to MAKE UP questions for the pictograph. We then look at several possibilities, including one of Mathy's, and one challenge problem.

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