Correction :

7 × 7 = 49	19 + 21 = 40
16 + 17 = 33	3 × 8 = 24
14 + 6 = 20	34 - 16 = 18
14 + 24 = 38	35 : 7 = 5
20 - 8 = 12	25 - 19 = 6
42 - 23 = 19	70 : 7 = 10
5 + 20 = 25	20 - 5 = 15
7 - 4 = 3	10 × 10 = 100
21 + 17 = 38	12 + 12 = 24
30 - 24 = 6	20 + 2 = 22