- The sum of the ones digit equal to 10
- The other digits are the same
Steps:
- The tens digit multiply by another tens digit plus one. In this case, the tens digit is 4, hence we multiply 4 by 5. 4 x 5 = 20. The product will be the last two digits of the answer.
- The product of the ones digit of the two numbers will be the first two digit of the answer.
Example 1:
57 x 53 = ?
Answer:
5 x 6 = 30
7 x 3 = 21
57 x 53 = ?
Answer:
5 x 6 = 30
7 x 3 = 21
57 x 53 = 3,021
Example 2:
81 x 89 = ?
Answer:
8 x 9 = 72
1 x 9 = 9
81 x 89 = ?
Answer:
8 x 9 = 72
1 x 9 = 9
81 x 89 = 7,209
Example 3:
114 x 116 = ?
Answer:
11 x 12 = 132
4 x 6 = 24
114 x 116 = ?
Answer:
11 x 12 = 132
4 x 6 = 24
114 x 116 = 13,224
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