1） 45 ÷〔78 －（25 ＋38 ）〕
2） 8×7分之4÷[1÷(3.2-2.95)]
=8×4/7÷[1÷0.25]
=8×4/7÷4
=8/7
3）20×[(2.44－1.8)÷0.4＋0.15]
4）430.8÷[14－(9.85＋1.07)]
5）[60－(9.5＋28.9)]÷0.18
6）20×[(2.44－1.8)÷0.4＋0.15]
7）0.8×〔15.5-(3.21+5.79)〕
8）0.8×[(10－6.76)÷1.2]
9）30.8÷[14－(9.85＋1.07)]
10）[60－(9.5＋28.9)]÷0.18
11）20×[(2.44－1.8)÷0.4＋0.15]
12）0.8×〔15.5-(3.21+5.79)〕
13）0.8×[(10－6.76)÷1.2]
14）[60－(9.5＋28.9)]÷0.18
= (60- 38.4)÷0.18
= 21.6 ÷0.18
= 120
15）20×[(2.44－1.8)÷0.4＋0.15]
= 20x (0.64 ÷0.4 +0.15)
= 20x(1.6 +0.15)
= 20 x1.75 = 35
16）0.8×[(10－6.76)÷1.2]
= 0.8 x(3.24÷1.2)
= 0.8 x 2.7
= 2.16
17）30.8÷[14－(9.85＋1.07)]
= 30.8 ÷ (14 - 10.92)
= 30.8÷3.08
= 10
18）0.8×〔15.5-(3.21+5.79)〕
= 0.8 x (15.5 - 9)
= 0.8 x 6.5
= 5.2
19）70×〔（42-42）÷18〕
=70 x (0÷18)
= 70x0
= 0
