Make a 10

Make a 10 (This strategy is used for 8 and 9):

First, students must know the 10 compliments of 8 and 9, 2 and 1 respectively.

 

When a number is added to 9, you take one away from the other number (adding it to the 9 making it 10), and then adding the number one smaller to 10.

6+9=

  • Take the other number (6)
  • Take one away (6-1=5) (know you are adding the 1 you took away to the 9 to make 10).
  • Add the new number to 10 (5 + 10 = 15)
  • 6+9=15

9+4

  • Take the other number (4)
  • Take one away (4-1=3) (know you are adding the 1 you took away to the 9 to make 10).
  • Add the new number to 10 (3 + 10 = 13)
  • 9+4=13

 

 

When a number is added to 8, you take two away from the other number (adding it to the 8 making it a 10), and then adding the number two smaller to 10.

3+8=

  • Take the other number (3)
  • Take two away (3-2=1) (know you are adding the 2 you took away to the 8 to make 10).
  • Add the new number to 10 (1 + 10 = 11)
  • 3+8=11

8+6

  • Take the other number (6)
  • Take two away (6-2=4) (know you are adding the 2 you took away to the 8 to make 10).
  • Add the new number to 10 (4 + 10 = 14)
  • 8+6=14