帮助一下，小学数学

显示全部楼层 · 2011-6-15 20:26:53

9.25×9.9 ﹢0.925
9.9×7.8
1.9＋1.99＋1.999＋1.9999
0.54÷0.15÷0.6

千问 · 2011-6-15 20:26:53

9.25×9.9 ﹢0.925=9.25×9.9+9.25×0.1=9.25×（9.9+0.1）=9.25×10=92.59.9×7.8=7.8×（10-0.1）=7.8×10-7.8×0.1=78-0.78=77.221.9＋1.99＋1.999＋1.9999=（2-0.1）+（2-0.01）+（2-0.001）+（2-0.0001）=2+2+2+2-0.1-0.01-0.001-0.0001=8-0.1111=7.88890.54÷0.15÷0.6=0.54÷（0.15×0.6）=0.54÷0.09=6...

千问 · 2011-6-15 20:26:53

9.25x9.9+9.25x0.1=9.25x(9.9+0.1)=9.25x10=92.5(10-0.1)x7.8=10x7.8-0.1x7.8=78-0.78=77.222-0.1+2-0.01+2-0.001+2-0.0001=8-0.1111=7.88890.54/0.6/0.15=0.9/0.15=6...

千问 · 2011-6-15 20:26:53

9.25×9.9 ﹢0.925=0.925×99+0.925=0.925×(99+1)=0.925×100=92.59.9×7.8=(10-0.1)×7.8=78-0.78=77.221.9＋1.99＋1.999＋1.9999=2×4-0.1-0.01-0.001-0.0001=8-0.1111=7.8...