Question

小学数学题:12.8+2.04×9.5简便运算？

四年级的12.8X2.04Ⅹ9.5的简便脱式计算

Answer 1

2.04*0.5=1.02

11.78=12.8-1.02

2.04*9.5+2.04*0.5=20.4

20.4+11.78=32.18

Answer 2

12.8+2.04×9.5
=12.8+2.04×(10－0.5)
=12.8+20.4－1.02
=33.2－1.02
=32.18

Answer 3

12.8十2.04x9.5
=12.8+2.08x(10-0.5)
=12.8+20.8-1.04
=33.6-1.04
=32.56

Answer 4

你的图片上是12.8×2.04×9.5
先计算12.8×2.04
=（12.5+0.3）×（2+0.04）
=12.5×2+12.5×0.04+0.3×2+0.3×0.04
=25+0.5+0.6+0.012
=25+1.1+0.012
=25+1+0.1+0.012
=26+0.112
所以12.8×2.04×9.5
=（26+0.112）×9.5
=（26+0.112）×（10-0.5）
=26×10-26×0.5+0.112×10-0.112×0.5
=260-13+1.12-0.056
=247+（1+0.12）-0.056
=（247+1）+（0.12-0.056）
=248+0.064
=248.064

Answer 5

12.8+2.04×9.5=12.8+2.04×(10-0.5)
=12.8+20.4-1.02
=12.8+19.38
=32.18