解答:解:(1)70×80=5600 3.7×0.5=1.85 3.2×100=320 8.9-3.8=5.1
(2)3.8+2.5+6.2=12.5 12-6.2-3.8=2 1.7+0.43+3.3=5.43 3.4-1.5-0.5=1.4
(3)
+
-
=
1.4×5=7 650-470=180 79+2.1=81.1
(4)3.14×3=9.42 6.7+3.4=10.1 2.01×0.4=0.804
+
=1
(5)3.99+5.2=9.19 23+6.68=29.68 7×0.08=0.56 0.25×0.4=0.1
(6)22×0.2=4.4 99.9+1=100.9 0.72÷6=0.12 3.9÷1.3=3
(7)0.8×0.8=0.64 5.88+3.12=9 1.9+2.1=4 26÷2.6=10
(8)340÷17=20 9.3÷0.3=31 13×4=52 3.6×5=18
(9)1.5×4=6 20×16=320 28×3=84 3.2÷4=0.8
(10)0.28×100=28 3200÷1000=3.2 0.5×100=50 4×0.125=0.5
(11)340+120=460
+
=
2.5÷5=0.5 4.95×10=49.5
(12)12-
-
=11 1÷0.25=4 5×0.13=0.65 12×0.05=0.6
(13)3.08÷0.1=30.8 0.35×6=2.1 25÷0.5=50 1.5×3=4.5
(14)4.3-2.7=1.6 8.1÷0.9=9 12÷1.2=10 0.48÷6=0.08
(15)2.6÷26=0.1 0.72×5=3.6 4.8+3.2=8 5.7÷0.3=19.