题目内容
简便计算.
0.25×3.86×4
16.7×2.1+10.8
0.43×102
9.8×5.6+9.8×4.4
76.1×17-76.1×7.
0.25×3.86×4
16.7×2.1+10.8
0.43×102
9.8×5.6+9.8×4.4
76.1×17-76.1×7.
分析:(1)运用乘法交换律简算;
(2)先算乘法,再算加法;
(3)把102看作100+2,运用乘法分配律简算;
(4)(5)运用乘法分配律简算.
(2)先算乘法,再算加法;
(3)把102看作100+2,运用乘法分配律简算;
(4)(5)运用乘法分配律简算.
解答:解:(1)0.25×3.86×4
=(0.25×4)×3.86
=1×3.86
=3.86;
(2)16.7×2.1+10.8
=35.07+10.8
=45.87;
(3)0.43×102
=0.43×(100+2)
=0.43×100+0.43×2
=43+0.86
=43.86;
(4)9.8×5.6+9.8×4.4
=9.8×(5.6+4.4)
=9.8×10
=98;
(5)76.1×17-76.1×7
=76.1×(17-7)
=76.1×10
=761.
=(0.25×4)×3.86
=1×3.86
=3.86;
(2)16.7×2.1+10.8
=35.07+10.8
=45.87;
(3)0.43×102
=0.43×(100+2)
=0.43×100+0.43×2
=43+0.86
=43.86;
(4)9.8×5.6+9.8×4.4
=9.8×(5.6+4.4)
=9.8×10
=98;
(5)76.1×17-76.1×7
=76.1×(17-7)
=76.1×10
=761.
点评:此题查了小数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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