The number is the product of the numbers 5 and 9 is 45. Then the sum of 5 and 8 will be 45.
Algebra is the study of mathematical symbols and the rule involves manipulating these mathematical symbols.
1 + 4 = 5
2 + 5 = 12
3 + 6 = 21
5 + 8 = ?
The pattern can be understood as
1 × (4 + 1) = 5
2 × (5 + 1) = 12
3 × (6 + 1) = 21
4 × (7 + 1) = 32
5 × (8 + 1) = 45
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