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Let's build and break! 🧱 THE THEME: Joining and Splitting. Math is the story of groups coming together or splitting apart.
Main skills from this lesson
UNIT 2: ADDITION AND SUBTRACTION
Addition means putting things together to find the TOTAL.
Let's start with 'One More'. Count the objects, then see what happens when we add one more!
If you have 4 fish and catch 1 more, how many fish do you have now?
How many birds altogether?
There are 3 birds on a tree. 2 more birds join them. Now there are 5 birds!
When we add 3 and 2, we get 5 as the sum.
+ = 3 + 2 = 5
How do we read '3 + 2 = 5'?
Alisha is playing on the beach. Help her add the objects she found!
Count the shells, sticks, and starfish.
If Alisha has 10 sticks and finds 3 more, how many does she have?
Make a group of 10 and then add.
It's much easier to count when we have a group of 10 first!
Get Busy: Use red and green counters to solve these!
What is 10 + 6?
Addition Using Number Line
Let's add 4 and 5. Start from 4 and count forwards 5 steps to reach 9.
4 + 5 = 9
0—1—2—3—[4] ™5 ™6 ™7 ™8 ™[9]—10
To add, we move FORWARDS (to the right) on the number line.
If you start at 7 and hop 5 steps forward, where do you land?
Counting Forwards and Column Addition
When we add bigger numbers, we use columns for Tens (T) and Ones (O).
Always add the Ones first, then add the Tens!
| T | O |
|---|---|
| 1 | 5 |
| + | 3 |
| 1 | 8 |
Rule: 5 + 3 = 8 (Ones). 1 + 0 = 1 (Tens). Total is 18!
In 53 + 36, what is the sum of the Ones (3 + 6)?
Many Ways to Make a Number!
The same number can be made by adding different combinations. Look at all the ways to make 5!
Did you know? 7 + 2 is the SAME as 2 + 7. It's like a math mirror!
If 7 + 2 = 9, then what is 2 + 7?
Adding Equal Groups
When every group has the same number, we call it Repeated Addition. It's the secret to multiplication!
Look at the erasers: 3 groups of 2 each.
2 + 2 + 2 = 6
[ ] + [ ] + [ ] = 6
3 groups of 2 = 6. We can say '3 twos are 6'!
If you have 4 groups of 2, how would you write the addition?
Let's Get Busy with Groups!
Imagine 4 circles on the floor. Each circle has 3 colorful counters.
[ ] [ ] [ ] [ ]
When we add the same number many times, we are finding the total of equal groups!
If you have 4 groups of 3, how many balls do you have altogether?
Let's add 4, 3, and 1.
You can add them in any order!
Strategy 1: (4 + 3) + 1 = 7 + 1 = 8
Strategy 2: 4 + (3 + 1) = 4 + 4 = 8
[ ] + [ ] + [ ] = 8
Try this! Does adding the last two numbers first give you the same sum? YES!
What is 2 + 3 + 5?
Adding Three Groups
Let's count balloons of different colors and find the total!
| Color | How Many |
|---|---|
| Blue | 3 |
| Red | 2 |
| Green | 5 |
| Total ✨ | 10 |
3 + 2 + 5 = 10 balloons altogether!
If you have 6 blue, 2 red, and 3 green balloons, how many in all?
The Make-10 Strategy
To add big numbers, break one number to make a 10 first!
Example: 6 + 7
6 + 7 ™ (3 + 3) + 7 ™ 3 + (3 + 7) ™ 3 + 10 = 13
Look for numbers that make 10: (1+9), (2+8), (3+7), (4+6), (5+5)!
If you are adding 5 + 8, how much from the 5 do you need to make the 8 into a 10?
Double Trouble!
Adding the same number twice is called a Double. You can use doubles to add even faster!
Example: 8 + 9
+ + (1) = 17 (Double 8) + 1 = 17
Near Doubles: If you know 5 + 5 = 10, then 5 + 6 must be 11!
If 7 + 7 = 14, what is 7 + 8?
Practice Your Doubles!
How fast can you double these numbers? Remember: a double is just a number added to itself.
What is 5 + 6 using the double fact 5 + 5?
Addition with Tens and Ones
Numbers are made of Tens and Ones. Let's add them up!
+ = 5 Pencils
Story Math: Hassan has 2 pencils. Ali has 3 pencils. Together they have 5!
If you have 1 ten and 1 one, what number do you have?
More Math Stories!
Help the kids in the neighborhood find their house numbers by adding the sums on their roofs!
If Ismail has a box of 12 bottles and adds 6 more, what is the total?
Let's count our friends!
When new friends join, we add them to the group to find the total.
If there are 6 yellow robots and 3 blue robots, how many robots are there in all?
What is Subtraction?
Subtraction means taking away! When we take something away, we have less than we started with.
The Picnic Challenge:
[] ™ 5 frogs - 2 jumped = 3 left
'One Less' is just counting BACKWARDS one step!
If you have 5 candies and eat 1, how many do you have left?
The Minus Sign (-)
We use the minus sign (-) to show subtraction.
5 - 2 = 3
We read this as: '5 minus 2 is equal to 3'.
[] ™ 4 - 2 = 2
Sharing is caring! Sabrin is giving some of her things to Mallika.
How do you read '5 - 2 = 3'?
Subtraction Facts
Did you know? Subtracting 0 doesn't change the number. Subtracting a number from itself always makes 0!
Number Line Hops:
To subtract 16 - 5, start at 16 and hop backwards 5 steps.
11 12 13 14 15 [16] 16 - 5 = 11
Hoping backwards on the number line is the same as taking away!
If you start at 10 and hop back 3 steps, what number do you reach?
Match the Petals!
Many different subtraction problems can have the same answer. Can you find them all in our math flowers?
If the center of the flower is 5, which of these is a matching petal?
Numbers are like Families!
Three numbers can live together in a fact family. They tell 4 different stories!
Example: 3, 7, and 10
10 - 4 = 6 0—1—2—3—4—5—[6] 7 8 9 10
If you know one addition fact, you already know a subtraction fact too!
In the family (3, 7, 10), if 7 + 3 = 10, then 10 - 7 =?
Counting Backwards
You don't always need a number line. You can count backwards in your head!
Example: 12 - 5
Start at 12 and count back 5 steps: 11, 10, 9, 8, 7.
So, 12 - 5 = 7.
19 ™ 18 ™ 17 ™ 16 ™ [15] 19 - 4 = 15
Put the big number in your head and count back using your fingers!
What is 19 - 4 if you count back 4 steps from 19?
The Ones and Tens Rule
When subtracting big numbers, always follow this order:
| Tens (T) | Ones (O) |
|---|---|
| 3 | 8 |
| - 1 | 5 |
| **2** | **3** |
Aboobakuru's Pencils: 9 pencils - 4 given away = 5 left!
If you have 46 and subtract 12, what is the result in the TENS column?
Real-World Subtraction
Let's use our subtraction skills to solve some everyday stories!
| Tens (T) | Ones (O) |
|---|---|
| 4 | 9 |
| - 1 | 7 |
| **3** | **2** |
Difference: When we compare ages or heights, we are finding the difference using subtraction!
If Danish has 49 blocks and his sister takes 17, how many are left?
Finding the Missing Part
Numbers work together in teams! If you know the total (Whole) and one part, you can find the other part.
Faizal's Beads: 54 - 32 = 22 beads left.
| Tens (T) | Ones (O) |
|---|---|
| 5 | 4 |
| - 3 | 2 |
| **2** | **2** |
Part-Part-Whole: The Whole is the big total. The Parts are the smaller numbers that make it up!
If the Whole is 10 and one Part is 6, what is the other Part?
Plus or Minus?
Can you figure out which math sign (+ or -) belongs in the sentence?
Operation Hint: Look at the answer! Did it grow or shrink?
Which sign (+ or -) makes this true: 15 ___ 5 = 10?
Addition or Subtraction?
Read the story carefully! If things are being taken away, subtract. If things are coming together, add.
| Tens (T) | Ones (O) |
|---|---|
| 7 | 8 |
| - 1 | 7 |
| **6** | **1** |
Bee Fact: One bee has 6 legs. Two bees have 12 legs! That's 6 + 6.
There are 31 horses and 5 more enter. Is this (+) or (-)?
What Do You Know?
It's time to show off your skills! Fill in the target flowers and use the color code to solve the grid.
Review Tip: If you're stuck on a big number like 99, try counting back in tens first!
Which number completes the target of 17 if you have 7?
Continue with quizzes, flashcards, or games when you are ready.