Đáp án_Giải thích các bước giải:
`11)` `0,5+1/3+0,4+5/7+1/6-4/35`
`=1/2+1/3+2/5+5/7+1/6-4/35`
`=(1/2+1/3+1/6)+(2/5+5/7-4/35)`
`=(3+2+1)/(6)+(14+25-4)/(35)`
`=(6)/(6)+(35)/(35)` (bước này có thể bỏ qua)
`=1+1`
`=2`
`12)` `8/9-1/72-1/56-1/42-1/30-1/20-1/12-1/6-1/2`
`=(8/9-1/72-1/56-1/42)+(-1/30-1/20-1/12-1/6-1/2)`
`=(448-7-9-12)/(7*8*9)+(-2-3-5-10-30)/(60)`
`=(420)/(7*2^2*2*3*3)+(-50)/(60)`
`=(5)/(2*3)+(-5)/(6)`
`=5/6-5/6`
`=0`
`13)` `(3-1/4+2/3)-(5+1/3-6/5)-(6-7/4+3/2)`
`=3-1/4+2/3-5-1/3+6/5-6+7/4-3/2`
`=(3-5-6)-3/2+(2/3-1/3)+(7/4-1/4)+6/5`
`=-8-3/2+1/3+6/4+6/5`
`=-8+1/3+6/5+3/2-3/2`
`=(-120+5+18)/(3*5)`
`=(-97)/(15)`
`14)` `1/3-3/4-3/5+1/64-2/9-1/36+1/15`
`=(1/3-3/5+1/15)+(-3/4-2/9-1/36)+1/64`
`=(5-6+1)/(15)-(27+8+1)/(36)+1/64`
`=0/15-36/36+1/64`
`=1/64-1`
`=(1-64)/64`
`=-63/64`
`15)` `(-5/9)*3/11+(-13/28)*3/11`
`=3/11*(-5/9-13/28)`
`=3/11*(-140-117)/(9*28)`
`=3/11*(-257)/252`
`=(-257)/(11*84)`
`=(-257)/(924)`
`16)` `(2 2/15*9/17*3/32):(-3/7)`
`=32/15*9/17*3/32*(-7)/(3)`
`=(32*3*3*3*(-7))/(3*5*17*32*3)` (bước này có thể bỏ qua)
`=(3*(-7))/(5*17)`
`=(-21)/(85)`
`17)` `((-3)/4+2/5):3/7+(3/5+(-1)/(4)):3/7`
`=(-3/4+2/5+3/5-1/4):3/7`
`=[(2/5+3/5)-(3/4+1/4)*7/3`
`=(5/5-4/4)*7/3` (bước này có thể bỏ qua)
`=(1-1)*7/3`
`=0*7/3`
`=0`
