问题
解答题
用递等式计算(能巧算的要巧算
(125+83)×32
16×78-(1440÷45+29)
513×63+36×513+513
216×27÷81+712÷89
125×320×25
5580÷[30+12×(361-356)].
答案
(1)(125+83)×32,
=208×32,
=(200+8)×32,
=200×32+8×32,
=6400+256,
=6656;
(2)16×78-(1440÷45+29),
=16×78-(32+29),
=16×78-61,
=1248-61,
=1187;
(3)513×63+36×513+513,
=513×(63+36+1),
=513×100,
=51300;
(4)216×27÷81+712÷89,
=5832÷81+712÷89,
=72+8,
=80;
(5)125×320×25,
=125×(8×40)×25,
=(125×8)×(40×25),
=1000×1000,
=1000000;
(6)5580÷[30+12×(361-356)],
=5580÷[30+12×5],
=5580÷[30+60],
=5580÷90,
=62.