题目内容
2220÷37= | 47×67= | 74×76= |
123123÷1001= | 3456×9999= | 489+507+505+492+497+509+500 |
1111.5÷2.5 | 0-1-2+3+4-5-6+7+8-…-97-98+99+100. |
解:(1)2220÷37=60;
(2)47×67=3149;
(3)74×76=5624;
(4)123123÷1001=123;
(5)3456×9999
=3456×(10000-1),
=3456×10000-3456,
=34560000-3456,
=34556544;
(6)489+507+505+492+497+509+500
=(500-11)+(500+7)+(500+5)+(500-8)+(500-3)+(500+9)+500,
=500×7+(7+5+9-11-8-3),
=3500-1,
=3499;
(7)1111.5÷2.5=444.6;
(8)0-1-2+3+4-5-6+7+8-…-97-98+99+100
=(3+4-1-2)+(7+8-5-6)+…+(100+99-97-98),
=4×(100÷4),
=4×25,
=100.
分析:(1)(2)(3)(4)(7)根据整数乘法与除法的运算法则计算即可;
(5)(6)可根据凑整法计算;
(8)可根据加法结合律计算.
点评:完成本题要注意分析式中数据的特点,然后运用合适的方法进行计算.
(2)47×67=3149;
(3)74×76=5624;
(4)123123÷1001=123;
(5)3456×9999
=3456×(10000-1),
=3456×10000-3456,
=34560000-3456,
=34556544;
(6)489+507+505+492+497+509+500
=(500-11)+(500+7)+(500+5)+(500-8)+(500-3)+(500+9)+500,
=500×7+(7+5+9-11-8-3),
=3500-1,
=3499;
(7)1111.5÷2.5=444.6;
(8)0-1-2+3+4-5-6+7+8-…-97-98+99+100
=(3+4-1-2)+(7+8-5-6)+…+(100+99-97-98),
=4×(100÷4),
=4×25,
=100.
分析:(1)(2)(3)(4)(7)根据整数乘法与除法的运算法则计算即可;
(5)(6)可根据凑整法计算;
(8)可根据加法结合律计算.
点评:完成本题要注意分析式中数据的特点,然后运用合适的方法进行计算.
练习册系列答案
相关题目