用简便方法计算:(要写计算过程.) ①25×125×8×40 ②52×66+33×52+52 ③37×99 ④45×101.
(1)25×125×8×40, =(25×40)×(125×8), =1000×1000, =1000000; (2)52×66+33×52+52, =52×(66+33+1), =52×100, =5200; (3)37×99, =37×(100-1), =37×100-37×1, =3700-37, =3663; (4)45×101, =45×(100+1), =45×100+45×1, =4500+45, =4545; |
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