1st Grade Math - Add and Subtract 10 to Two-Digit Numbers: CCSS.MATH.CONTENT.1.NBT.C.5

1

$\frac{\begin{array}[b]{r}75\ -\ 10\end{array}}{ \ \ \space}$

Explanation

When we subtract from a two digit number, the only number that changes in our answer is the tens position, and it will always go down by . Mentally, we can subtract from the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}75\ -\ 10\end{array}}{ \ \ \ \ \space65}$

2

$\frac{\begin{array}[b]{r}70\ +\ 10\end{array}}{ \ \ \space}$

Explanation

When we add to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by . Mentally, we can add to the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}70\ +\ 10\end{array}}{ \ \ \ \space80}$

3

$\frac{\begin{array}[b]{r}70\ -\ 10\end{array}}{ \ \ \space}$

Explanation

When we subtract from a two digit number, the only number that changes in our answer is the tens position, and it will always go down by . Mentally, we can subtract from the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}70\ -\ 10\end{array}}{ \ \ \ \space60}$

4

$\frac{\begin{array}[b]{r}20\ -\ 10\end{array}}{ \ \ \space}$

Explanation

When we subtract from a two digit number, the only number that changes in our answer is the tens position, and it will always go down by . Mentally, we can subtract from the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}20\ -\ 10\end{array}}{ \ \ \ \space10}$

5

$\frac{\begin{array}[b]{r}35\ +\ 10\end{array}}{ \ \ \space}$

Explanation

When we add to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by . Mentally, we can add to the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}35\ +\ 10\end{array}}{ \ \ \ \space45}$

6

$\frac{\begin{array}[b]{r}10\ +\ 10\end{array}}{ \ \ \space}$

Explanation

When we add to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by . Mentally, we can add to the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}10\ +\ 10\end{array}}{ \ \ \ \space20}$

7

$\frac{\begin{array}[b]{r}75\ +\ 10\end{array}}{ \ \ \space}$

Explanation

When we add to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by . Mentally, we can add to the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}75\ +\ 10\end{array}}{ \ \ \ \space85}$

8

$\frac{\begin{array}[b]{r}60\ -\ 10\end{array}}{ \ \ \space}$

Explanation

When we subtract from a two digit number, the only number that changes in our answer is the tens position, and it will always go down by . Mentally, we can subtract from the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}60\ -\ 10\end{array}}{ \ \ \ \ \space50}$

9

$\frac{\begin{array}[b]{r}70\ -\ 10\end{array}}{ \ \ \space}$

Explanation

When we subtract from a two digit number, the only number that changes in our answer is the tens position, and it will always go down by . Mentally, we can subtract from the number in the tens place to find our answer.

$\frac{\begin{array}[b]{r}70\ -\ 10\end{array}}{ \ \ \ \ \space60}$

10

$\frac{\begin{array}[b]{r}35\ +\ 10\end{array}}{ \ \ \space}$

Explanation

When we add to a two digit number, the only number that changes in our answer is the tens position, and it will always go up by . Mentally, we can add to the number in the tens place to find our answer.