Multiply 74 × 101 by inspection

Question

Multiplying a two-digit number by 101 has an answer you can almost see without calculating. Solve in your head. What is 74 	imes 101? Aim: under 5 seconds.

Accepted Answer

Since 101 = 100 + 1, you get the number shifted two places plus itself: 74 	imes 101 = 7400 + 74 = 7474. So 74 	imes 101 = \mathbf{7474}. For any two-digit number, times-101 simply writes the number twice. Takeaway. Times-101 on a two-digit number "ab" gives "abab." More generally, 	imes 101 = 	imes 100 + 	imes 1, shift and add the original.

Multiply 74 × 101 by inspection

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