3: A
4: C
三
1:24 10 0.5 2/3
0.027 3又3/5 27/8 20
2: 1050÷7-24x4 10.5-6.25-3.75+7.5
=150-96 =(10.5+7.5)-(6.25+3.75)
=54 =18-10
=8
3/8x30+2÷8/3 56x(1+4/7)÷8/11
=3/8x30+2x3/8 =56×11/8x(1+4/7)
=3/8x(30+2) =77x(1+4/7)
=3/8×32 =77x1+77x4/7=12 =77+44 =121
5/8÷[13/12-(1/12+1/4)]
=5/8÷[13 |