Adding Means Putting Groups Together
Lumi sits at a sunny picnic table outdoors, carefully placing a group of red apples and a group of yellow apples into one big bowl, smiling as the bowl fills up with fruit.
- Explain that adding means joining two groups into one group.
- Identify the total as the number you get after putting two groups together.
- Predict what happens to the number of objects when two groups are joined.
- Calculate a simple sum by counting all objects after joining two groups.
Key terms
- addition
- Putting two or more groups together to make one bigger group.
- sum
- The total number you get after you add groups together.
- addend
- One of the groups, or numbers, you are joining together.
- plus sign
- The little + symbol that tells you to add groups together.
Joining Two Groups
When you add, you start with two separate groups and slide them into one place. None of the items disappear and none get added by magic — every single object that was in either group is still there in the new big group. Adding is just bringing them together so you can count them all at once.
Finding the Total
After you join the groups, the answer is called the sum or the total. To find it, count every object in the combined group, starting from one and going up. The last number you say is the sum. A neat shortcut is to start at the bigger group's number and count on, but counting all of them always works too.
Worked examples
Add 2 red apples and 3 yellow apples.
- Put both groups into one bowl together.
- Count every apple: 1, 2, 3, 4, 5.
- The last number you say is the total.
Answer: 5 apples
Find the sum of 4 birds and 2 birds.
- Start at the bigger number, 4.
- Count on two more: 5, 6.
- You stop at 6, so that is the total.
Answer: 6 birds
Activity
Drag each group of apples into the big bowl to put them together.
Practice
Theo has 3 stickers and finds 2 more stickers. How many stickers does he have now?
Join a group of 5 marbles and a group of 1 marble, then count them all.
Common mistakes to avoid
- Adding makes things disappearAdding never removes objects; it brings every item into one group, so the total is always at least as big as each group.
- The answer is just the bigger groupYou must count both groups together, because the smaller group still adds its objects to the total.
Check your understanding
There are 4 frogs on a lily pad and 2 frogs in the water. You put them all together. How many frogs are there now?
Maya has 1 block. She gets 3 more blocks. She puts them all in one pile. Which is true about her pile?
Recap
Adding means putting two groups together to make one group. The total, or sum, is the number you get when you count every object after joining. Adding always makes a group the same size or bigger, never smaller.
Reflect
When have you put two groups of toys or snacks together to find out how many you have in all?