题目内容
脱式计算.
180÷9-18 | (48+52)÷5 | 100-25×4 | 20+80×3 | 7×(34+56) | 105×2×5. |
分析:(1)先算除法,再算减法;
(2)先算小括号里面的加法,再算括号外的除法;
(3)先算乘法,再算减法;
(4)先算乘法,再算加法;
(5)先算小括号里面的加法,再算括号外的乘法;
(6)运用乘法结合律简算.
(2)先算小括号里面的加法,再算括号外的除法;
(3)先算乘法,再算减法;
(4)先算乘法,再算加法;
(5)先算小括号里面的加法,再算括号外的乘法;
(6)运用乘法结合律简算.
解答:解:(1)180÷9-18,
=20-18,
=2;
(2)(48+52)÷5,
=100÷5,
=20;
(3)100-25×4,
=100-100,
=0;
(4)20+80×3,
=20+240,
=260;
(5)7×(34+56),
=7×90,
=630;
(6)105×2×5,
=105×(2×5),
=105×10,
=1050.
=20-18,
=2;
(2)(48+52)÷5,
=100÷5,
=20;
(3)100-25×4,
=100-100,
=0;
(4)20+80×3,
=20+240,
=260;
(5)7×(34+56),
=7×90,
=630;
(6)105×2×5,
=105×(2×5),
=105×10,
=1050.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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