1, a)1+1/3+1/9+1/27+1/81
=1+[(1+1/3+1/9+1/27)-(1/3+1/9+1/27+1/81)]:3
=1+(1-1/81):3
=1+80/81:3
=1+80/243
=323/243
b)37,52+4,7x2,3-9,8
=37,52+10,81-9,8
=48,33-9,8
=38,53
2,a)0,125x6,135x24
=0,125x6,135x3x8
=0,125x8x(6,135x3)
=1x18,405
=18,405
b)5m2 7dm2+2,6m2+3,33m2
=5,07m2+3,33m2+2,6m2
=8,4m2+2,6m2
=11m2
3, a)x:4,37=5,6 ( dư 1,53)
x=5,6x4,37+1,53
x=26,002
b)13,5x( x:5,6)=36,45
x:5,6=36,45:13,5=2,7
x=2,7x5,6
x=15,12
4,a)5xXx8,3=20,75
5xX=20,75:8,3=2,5
X=2,5:5
X=0,5
b)5,75+Xx1,25=8 1/4
5,75+Xx1,25=33/4
Xx1,25=33/4-5,75=2,5
X=2,5:1,25
X=2
