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(2012•商丘模拟)计算.546-398=457+199=2.2×101=32×0.125×25=5.4×99+5.4=(37+521+214)×21=999×999+999=18.7×101-18.7=

题目详情
(2012•商丘模拟)
计算.
546-398=
457+199= 2.2×101=
32×0.125×25= 5.4×99+5.4=
3
7
+
5
21
+
2
14
)×21=
999×999+999= 18.7×101-18.7=
▼优质解答
答案和解析

(1)546-398,
=546-400+2,
=146+2,
=148;

(2)457+199,
=457+200-1,
=657-1,
=656;

(3)2.2×101,
=2.2×(100+1),
=2.2×100+2.2×1,
=220+2.2,
=222.2;

(4)32×0.125×25,
=8×4×0.125×25,
=(8×0.125)×(4×25),
=1×100,
=100;

(5)5.4×99+5.4,
=5.4×(99+1),
=5.4×100,
=540;

(6)(
3
7
+
5
21
+
2
14
)×21,
=
3
7
×21+
5
21
×21+
2
14
×21,
=9+5+3,
=17;

(7)999×999+999,
=999×(999+1),
=999×1000,
=999000;

(8)18.7×101-18.7,
=18.7×(101-1),
=18.7×100,
=1870.