Adding within 100 worksheets
Aligned with Common Core 1.NBT.C.4
Printable worksheets for adding and subtracting with tens: adding tens, adding tens to any number, adding a two-digit and a one-digit number, and taking away tens.
The worksheets
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Adding within 100 Chart
Adding tens, adding tens to a number, making the next ten, and taking away tens.
Add Tens
Adding multiples of 10 like 30 + 40, with rod pictures to count.
Add Tens to a Number
Adding a multiple of 10 to a two-digit number, like 34 + 20, in a lined-up grid.
Two-Digit Plus One-Digit
Adding a one-digit number to a two-digit number in a grid, sometimes making a new ten.
Take Away Tens
Subtracting multiples of 10, like 70 - 30, with rod pictures to cross out. Matches 1.NBT.C.6.
Print the whole packet
One copy of every sheet above, in order. Tap + for more copies (up to 10).
For the parent or teacher
What it is
In first grade, adding within 100 means problems like 40 + 30, 52 + 20 and 46 + 7. Kids use what they know about tens and ones. Tens go with tens and ones go with ones. When the ones add up to 10 or more, those ones make a new ten.
What comes next
In second grade, adding and subtracting two-digit numbers with regrouping.
How to teach it
- Use base-ten blocks or drawings. Put the rods together, then the cubes.
- For adding tens, think of it like adding small numbers. 4 tens + 3 tens = 7 tens, which is 70.
- For 46 + 7, the 4 tens stay put. 6 + 7 = 13, which is another ten and 3 ones, so 53.
- Line numbers up in the grid so tens are over tens and ones are over ones.
Common mistakes
- Adding the one-digit number to the tens, so 46 + 7 becomes 116.
- Forgetting to carry the new ten when the ones add up to 10 or more.
- Writing 7 instead of 70 for 40 + 30.