| 560-476÷17×5 | +5.13+ +0.87 | (20.2×0.4+7.88)÷4.2 |
÷[( )× ] | 7.6× +7.6×0.4 | (0.75+ )÷ × . |
(1)560-476÷17×5,
=560-28×5,
=560-140,
=420;
(2)
+5.13+
+0.87,=(
+
)+(5.13+0.87),=1+6,
=7;
(3)(20.2×0.4+7.88)÷4.2,
=(8.08+7.88)÷4.2,
=15.96÷4.2,
=3.8;
(4)
÷[(
)×
],=
÷[
×
],=
÷
,=3;
(5)7.6×
+7.6×0.4,=7.6×(
+0.4),=7.6×1,
=7.6;
(6)(0.75+
)÷
×
,=
÷
×
,=
×
,=1.
分析:(1)先算除法,再算乘法,最后算减法;
(2)根据加法交换律和结合律进行计算;
(3)先算乘法,再算加法,最后算除法;
(4)先算加法,再算乘法,最后算除法;
(5)根据乘法分配律进行计算;
(6)先算加法,再算除法,最后算乘法.
点评:四则混合运算,先弄清运算顺序,然后再进一步计算即可,能简算的要简算.