Operations & Algebraic Thinking
Understanding Addition
Addition as putting together and adding to.
Putting Groups Together
You already know how to count a group of objects. Addition is what happens when you start with one group and put more objects with it. Once the groups are together, you count them all as one bigger group.
Definition — Addition
There are two ways to think about addition. 'Putting together' means you start with two separate groups, like 3 red blocks and 4 blue blocks, and combine them into one group. 'Adding to' means you start with one group and more objects join it, like 3 birds on a branch and 4 more birds landing.
Worked Example — Putting Together
Worked Example — Adding To
Tip
Common Mistakes
Recounting the whole group from 1 every time, even when counting on from the larger number would be faster.
Start at the bigger number and count on by the smaller number. For 2 + 5, start at 5 and count on 2 more: 6, 7.
Losing track of how many were counted on, and stopping too early or too late.
Use fingers or a number line to keep track of each count while counting on, one finger per number said.
Key Takeaways
- Addition joins groups together to find how many there are in all.
- The answer to an addition problem is called the sum.
- Counting on from the larger group is a fast way to add.
Summary
Addition combines groups into one bigger group. The next lesson looks at the opposite move — taking a group apart — which is called subtraction.
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