Deriver +/- (Adding/Subtracting)

Uses flexible strategies such as Break Apart to Make Ten (BAMT) and derived combinations (e.g., "7+7 is 14, so 7+8 is 15) to solve all types of problems. Can simultaneously think of 3 numbers within a sum, and can move part of a number to another, aware of the increase in one and the decrease in another. May solve simple cases of multidigit addition (sometimes subtraction) by counting by tens and/or ones.

Activities

You may see this:

Linked Image to Sign In/Sign Up page

Other Examples:

  • Asked, “What’s 7 plus 8?, thinks: 7 + 8 -> 7 + [7 + 1] -> [7 + 7] + 1 = 14 + 1 = 15. Or, using BAMT, thinks: 8 + 2 = 10, so separate 7 into 2 and 5, add 2 and 8 to make 10, then add 5 more, so 15.  
  • Asked “What’s 20 + 34?”, child uses connecting cubes to count up 20, 30, 40, 50 plus 4: 54.  
  • Using BAMT, thinks "9 + 6…I break 1 off the 6 and put it on the 9 to make 10. Then the 10 and the left-over 5 is 15.” 

Help your student become a(n) Deriver +/- (Adding/Subtracting)

These activities challenge children to solve all types of arithmetic problems using flexible strategies such as Break Apart to Make Ten (BAMT- 9 + 6, take 1 off the 6 to make 10, then 10 and 5 is 15) and derived combinations (e.g., “7+7 is 14, so 7+8 is 15)  problems. So children are encouraged to move part of a number to another, aware of the increase in one and the decrease in another. Encourage children to learn a variety of strategies.

Crossing Decades
Crossing Decades
21
21
Add it Up!
Add it Up!
Decade Spin
Decade Spin
Tic-Tac-Total
Tic-Tac-Total
Ten Spot
Ten Spot
Grid Race
Grid Race
Toy Shop: Deriver
Toy Shop: Deriver
Chocolate Chip Count
Chocolate Chip Count

Special Thanks To

Institute of Education Sciences
The research reported here was supported by the Institute of Education Sciences, U.S. Department of Education, through grant numbers R305K050157, R305A120813, R305A110188, and R305A150243. to the University of Denver. The opinions expressed are those of the authors and do not represent views of the Institute or the U.S. Department of Education.