Đáp án+Giải thích các bước giải:
a)`1/2(2/9+3/7-5/27)`
`=1/2(42/189+81/189-35/189)`
`=1/2 . 88/189`
`=44/189`
`b)(-5/28+1,75+8/35):(-3 9/20)`
`=(-5/28+175/100+8/35):(-69/20)`
`=(-5/28+7/4+8/35):(-69/20)`
`=(-25/140+245/140+32/140):(-69/20)`
`=9/5:(-69/20)`
`=9/5.(-20/69)`
`=``-12/23`
`c)1/3 . 5/7-7/27 . 36/14`
`=5/21-2/3`
`=5/21-14/21`
`=(-9)/21`
`=(-3)/7`
`d)70,5-528:15/2`
`=70,5-528.2/15`
`=70,5-70,4`
`=0,1`
Bài 5:
`a)25%-5/4+1(5)/(6)`
`=1/4-5/4+11/6`
`=(-4)/4+11/6`
`=(-1)+11/6`
`=(-6)/6+11/6`
`=5/6`
`b)75%:2(1)/(5)-(0,5)².(-7)+2,5(7(2)/(3)-5(2)/(3))`
`=3/4: 11/5-1/4.(-7)+2,5(23/3-17/3)`
`=3/4 . 5/11+7/4+2,5.2`
`=15/44+7/4+5`
`=15/44+77/44+220/44`
`=78/11`
`c)45:2(4)/(7)+50%-1,25`
`=45:18/7+1/2-5/4`
`=45.7/18+1/2-5/4`
`=35/2+1/2-5/4`
`=18-5/4`
`=72/4-5/4`
`=67/4`
`d)350%:105/24+4(5)/(6):2-(0,5)².30%`
`=7/2 . 24/105+29/6 : 2-1/4 . 3/10`
`=4/5+29/12-3/40`
`=48/60+145/60-3/40`
`=193/60-3/40`
`=386/120-9/120`
`=377/120`
`e,f,g,h`:(ảnh)
