Finding Unknown Number in an Equation

Sian bought some CDs for $11 each and a CD case for $4. The total cost was $37 (n is the number of CDs bought).

Write an equation for..

Two different numbers a and b, add to 11.

Write an equation for..

Janna and Eugene have a total of $20, use j and e as the unknowns.

8 + ? = 14

• 3

• 4

• 5

• 6

4 + ? = 11

• 6

• 7

• 8

• 9

? + 5 = 12

• 5

• 6

• 7

• 8

? + 8 = 13

• 5

• 4

• 6

• 7

9 - ? = 3

• 6

• 5

• 7

• 4

10 - ? = 4

• 5

• 6

• 7

• 4

? - 5 = 8

• 14

• 13

• 12

• 11