脱式计算.(能简算的要简算)7.02×1.02 1.125÷0.092001×0.54+2001×0.46 0.64×0.25+0.750.78÷26+0.5×0.02 [2.8-2.8×(2.8-2.8)]÷0.78×[1÷(3.2-2.95)] 33.4-26.465÷(2.6+4.1)
问题描述:
脱式计算.(能简算的要简算) 7.02×1.02 |
1.125÷0.09 |
2001×0.54+2001×0.46 | 0.64×0.25+0.75 |
0.78÷26+0.5×0.02 | [2.8-2.8×(2.8-2.8)]÷0.7 |
8×[1÷(3.2-2.95)] | 33.4-26.465÷(2.6+4.1) |
答
(1)7.02×1.02,
=7.02×(1+0.02),
=7.02+7.02×0.02,
=7.02+0.1404,
=7.1604;
(2)1.125÷0.09,
=112.5÷9,
=12.5;
(3)2001×0.54+2001×0.46,
=2001×(0.54+0.46),
=2001×1,
=2001;
(4)0.64×0.25+0.75,
=0.16+0.75,
=0.91;
(5)[2.8-2.8×(2.8-2.8)]÷0.7,
=[2.8-2.8×0]÷0.7,
=2.8÷0.7,
=4;
(6)0.78÷26+0.5×0.02,
=0.03+0.01,
=0.04;
(7)8×[1÷(3.2-2.95)],
=8×[1÷0.25],
=8×4,
=32;
(8)33.4-26.465÷(2.6+4.1),
=33.4-26.465÷6.7,
=33.4-3.95,
=29.45.
答案解析:(1)先把1.02看作(1+0.02),运用乘法分配律计算;
(2)把被除数和除数分别扩大100倍再计算;
(3)运用乘法分配律简算;
(4)先算乘法,再算加法;
(5)先算除法和乘法,再算加法;
(6)小括号内的结果为0,中括号内的结果为2.8,最后算括号外的;
(7)先算小括号内的,再算中括号内的,最后算括号外的;
(8)先算小括号内的,再算括号外的除法,最后算减法.
考试点:小数四则混合运算;运算定律与简便运算.
知识点:此题考查了运算定律与简便运算,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简便计算.