What are factors? We read about factors in Chapter 6. We found that it is easy to multiply by 20 because 2 and 10 are factors of 20, and it is easy to multiply by both 2 and 10.
It is easy to multiply by 22 because 22 is 2 times 11, and it is easy to multiply by both 2 and 11.
It is easy to multiply by 33 because 33 is 3 times 11, and it is easy to multiply by both 3 and 11.
Whenever you have to multiply any number by a multiple of 11—such as 22 (2 × 11), 33 (3 × 11) or 44 (4 × 11)—you can combine the use of factors and the shortcut for multiplication by 11.
For instance, if you want to multiply 16 by 22, it is easy if you see 22 as 2 × 11. Th en you multiply 16 by 2 to get 32, and use the shortcut to multiply 32 by 11.
It is easy to multiply by 22 because 22 is 2 times 11, and it is easy to multiply by both 2 and 11.
It is easy to multiply by 33 because 33 is 3 times 11, and it is easy to multiply by both 3 and 11.
Whenever you have to multiply any number by a multiple of 11—such as 22 (2 × 11), 33 (3 × 11) or 44 (4 × 11)—you can combine the use of factors and the shortcut for multiplication by 11.
For instance, if you want to multiply 16 by 22, it is easy if you see 22 as 2 × 11. Th en you multiply 16 by 2 to get 32, and use the shortcut to multiply 32 by 11.
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