Take out some base-ten blocks or similar. We can use them to practice adding
and subtracting 1 or 10.
Let’s start with the number 25. Make the number 25 with your blocks. You will
need 2 tens and 5 ones.
25
Now, let’s add 1. How many do you have now?
Now, start with 25 again. This time, subtract, or take away, 10 blocks.
25 – 10 =
This time, let’s add 10! Start with 25, and add ten blocks. We can use the
blocks, and we can use what we know about addition to help us! Add the tens
(2 + 1), and then add the ones (5 + 0).
25 + 10 =
Start with 25 again, and subtract 1. This is an easy one! Take your 25
blocks, and take one away!
25 - 1 =
You are doing a great job using base-ten blocks to add and subtract by 1 and
10. Now, let’s use a hundred chart!
A hundred chart can help us add and subtract by 1 and 10. We can use the
hundred chart to learn how to move to add and subtract.
Let’s start on 57. Find 57 on the hundred chart. Follow these movements on
the hundred chart:
- If we add 1, we move one space to the right.
- If we subtract 1, we move once space to the left.
- If we add 10, we move one row straight down.
- If we subtract 10, we move one row straight up.
Are you ready to give it a try? Here’s the first problem:
57 + 1
Use the steps above! If we add 1, we move to the right one space.
Let’s keep using the hundred chart!
57 - 1
If we subtract 1, move to the left!
Now let’s add and subtract by 10 with the hundred chart.
57 + 10
Move down one row!
Finally, let’s subtract 10.
57 - 10
Move straight up one row.
Now you know how to use a hundred chart to help you add and subtract by 1 and
10!