missing numbers

What's the missing number?

• 10
• 11
• 9
• 20

What's the missing number?
10, 9, 8, 7, ___

• 11
• 5
• 6
• 8

What's the missing number?

• 83
• 91
• 81
• 80

What's the missing number?
6, 7, 8, ___, 10

• 8
• 5
• 11
• 9

What's the missing number?
33, 34, 35, 36, ___

• 38
• 37
• 36
• 39

• 6,7,8

• 4,5,6

• 8,9,10

• 16,18

• 18,20

____ + 5 = 7 - 1

• 1

• 2

• 8

• 3

6 + 4 = ___ + 5

• 10
• 5
• 2
• 16

10 - 3 = ___ + 4

• 4
• 13
• 7
• 3