《2025年通城学典计算能手四年级数学下册青岛版》

一、解方程。
5x÷2 = 70
4.2x + 6.2×3 = 31.2
(0.3x + 0.2x)÷60 = 2
5x + 3x = 12.8
8x - 1.6x = 3.2
x - 48 + 22 = 26.8
10.5 + 3x = 16.2
7(x - 36) = 35.7
2.5x - 0.5÷0.2 = 7.5
4x - 18 = 0.24
(3x - 2)×4 = 52
5.1x - 3.5x = 0.8
8x + 2.3 = 18.3
x÷(2.5×8) = 0.16
6x÷3 = 1.98

答案： x = 28 x = 3
x = 240
x = 1.6 x = 0.5
x = 52.8
x = 1.9 x = 41.1
x = 4
x = 4.56 x = 5
x = 0.5
x = 2 x = 3.2
x = 0.99

二、计算下面各题，怎样简便就怎样计算。
8.88×0.125
30.1×87 + 3.01×130
90.75÷[(5.4 - 1)×1.5]
68.5÷1.25÷0.8
175×2.5 + 2.5×25
7×[2.46÷(5.1 - 4.8)]
4.56 - (1 + 0.4)×3.2
3.62 + (5.6×10.1 - 0.98)
5.4÷[6.8÷(3 - 1.3)]
(480 - 450÷18)×1.5
180÷[75×(70 - 68)]
15.65 - (2.65 + 2.9) - 7.1
5×[27.3 - (7.1 + 2.7)]
7.32×0.25 + 2.68÷4
(0.57÷0.1 + 5.1)÷0.54

答案： 1.11 3010 13.75
68.5 500 57.4
0.08 59.2 1.35
682.5 1.2 3
87.5 2.5 20