题目内容
| 计算下面各题,能简算的要简算. 3.27+6.4+2.73+4.6 |
60-18.27-1.73 | 99×47 |
| 102×12+98×12 | (210-62÷31)×4 | 25×16. |
分析:(1)运用加法交换律和结合律简算;
(2)运用减法的性质简算;
(3)把99看作100-1,运用乘法分配律的逆运算简算;
(4)运用乘法分配律的逆运算简算;
(5)先算括号内的除法,原式变为(210-2)×4,把210看作 200+10,运用乘法分配律计算;
(6)把16拆成4×4后,再据乘法结合律简算.
(2)运用减法的性质简算;
(3)把99看作100-1,运用乘法分配律的逆运算简算;
(4)运用乘法分配律的逆运算简算;
(5)先算括号内的除法,原式变为(210-2)×4,把210看作 200+10,运用乘法分配律计算;
(6)把16拆成4×4后,再据乘法结合律简算.
解答:解:(1)3.27+6.4+2.73+4.6,
=(3.27+2.73)+(6.4+4.6),
=6+11,
=17;
(2)60-18.27-1.73,
=60-(18.27+1.73),
=60-20,
=40;
(3)99×47,
=(100-1)×47,
=100×47-47,
=4700-47,
=4653;
(4)102×12+98×12,
=(102+98)×12,
=200×12,
=2400;
(5)(210-62÷31)×4,
=(210-2)×4,
=(200+10-2)×4,
=200×4+8×4,
=800+32,
=832;
(6)25×16,
=25×4×4,
=100×4,
=400.
=(3.27+2.73)+(6.4+4.6),
=6+11,
=17;
(2)60-18.27-1.73,
=60-(18.27+1.73),
=60-20,
=40;
(3)99×47,
=(100-1)×47,
=100×47-47,
=4700-47,
=4653;
(4)102×12+98×12,
=(102+98)×12,
=200×12,
=2400;
(5)(210-62÷31)×4,
=(210-2)×4,
=(200+10-2)×4,
=200×4+8×4,
=800+32,
=832;
(6)25×16,
=25×4×4,
=100×4,
=400.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.
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