分析:(1)先算32×2,然后在結(jié)果中從后向前數(shù)出一位,點(diǎn)上小數(shù)點(diǎn)即可;
(2)先算2×13,然后在結(jié)果中從后向前數(shù)出兩位,點(diǎn)上小數(shù)點(diǎn)即可;
(3)先算5×12,然后在結(jié)果中從后向前數(shù)出三位,點(diǎn)上小數(shù)點(diǎn)即可;
(4)(6)(7)(9)(16)把被除數(shù)和除數(shù)分別擴(kuò)大10倍,再計(jì)算;
(5)0乘任何數(shù)都得0;
(8)先算8×12,然后在結(jié)果中從后向前數(shù)出兩位,點(diǎn)上小數(shù)點(diǎn)即可;
(10)(15)注意小數(shù)點(diǎn)對(duì)齊;
(11)從個(gè)位乘起;
(12)先算125×8,然后在結(jié)果中從后向前數(shù)出兩位,點(diǎn)上小數(shù)點(diǎn)即可;
(13)先算6×5,然后在結(jié)果中從后向前數(shù)出一位,點(diǎn)上小數(shù)點(diǎn)即可;
(14)先算4×5,然后在結(jié)果中從后向前數(shù)出兩位,點(diǎn)上小數(shù)點(diǎn)即可.
解答:解:
3.2×2=6.4 |
0.2×1.3=0.26 |
0.05×1.2=0.06 |
0.6÷0.3=2 |
5.46×0=0 |
2.5÷0.5=5 |
1.6÷0.5=3.2 |
0.8×1.2=0.96 |
0.9÷0.6=1.5 |
8-3.54=4.46 |
25×4=100 |
1.25×8=10 |
0.6×5=3 |
0.4×0.5=0.2 |
6.3÷7=0.9 |
3.8÷3.8=1 |
點(diǎn)評(píng):小數(shù)乘法,先把小數(shù)當(dāng)整數(shù)乘,乘完之后所有因數(shù)的小數(shù)點(diǎn)加起來(lái)共有幾位,積上面就點(diǎn)幾位小數(shù)點(diǎn).注意如果碰到因數(shù)有零的算式,要先加上零,再點(diǎn)小數(shù)點(diǎn).
小數(shù)除法,如果除數(shù)是小數(shù),先把它擴(kuò)大成整數(shù),被除數(shù)也擴(kuò)大相應(yīng)的倍數(shù),其他就按整數(shù)除法做.