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计算. (1)2.58×1.9 (2)10.8÷1.2 (3)4.5÷0.5÷9 (4)0.32×1.25×0.25

编辑:chaxungu时间:2026-04-27 13:35:58分类:小学数学题库

计算。(能简算的要简算)
(1)2.58×1.9(2)10.8÷1.2
(3)4.5÷0.5÷9(4)0.32×1.25×0.25
(1)2 .58 ×1 .9
=2.58×(2-0.1)
=2.58×2-2.58×0.1
=5.16-0.258
=4.902
(2)10 .8 ÷1 .2
=10.8÷(0.2×6)
=10.8÷0.2÷6
=54÷6
=9
(3)4 .5 ÷0 .5 ÷9
=4.5÷(0.5×9)
=4.5÷4.5
=1
(4)0 .32 ×1 .25 ×0 .25
=(0.4×0.8)×1.25×0.25
=(0.8×1.25)×(0.4×0.25)
=1×0.1
=0.1