3.68×4.79＋6.32×4.79
=(3.68＋6.32)×4.79
=10×4.79
=47.9
26.86×25.66－16.86×25.66
=(26.86－16.86)×25.66
=10×25.66
=256.6
5.7×99＋5.7
=5.7×(99＋1)
=5.7×100
=570
34×9.9
=34×(10－0.1)
=34×10－34×0.1
=340－3.4
=336.6
57×101
=57×(100＋1)
=57×100＋57×1
=5757
7.8×1.1
=7.8×(1＋0.1)
=7.8×1＋7.8×0.1
=7.8＋0.78
=8.58
