Finding the unknown in Number Sentences

Front

Dave had 14 D.V.D's. Dave bought some more and now has 22 D.V.D.'s. How many D.V.D's did Dave buy?

Back

_ + 14 = 22

Front

21 + _ = 30

Back

9

Front

19 - _ = 8

Back

11

Front

Sean has 15 marbles. Peter won 6 of Sean's marbles in a game. How many marbles does Sean now have?

Back

9

Front

How many more oranges did Mummy use if she used 16 initially and 25 altogether?

Back

_ + 16 = 25

Front

28 - 13 = _

Back

15

Front

20 + _ = 32

Back

12

Front

13 + _ = 32

Back

19

Front

Darryl is 34 years old. His brother, Darren, is 11 years younger than him. How old is Darren?

Back

23

Front

Sarah and Angel together have $18. If Sarah has $8, how much money does Angel have?

Back

$18 - $8 = $10