t.1
a) 25+X=40
X=15
b) 18+X=28
X=10
c) 27+X=45
X=18
d) 53+X=60
X=7

t.2
a)X+15=30
X=15
b) X+30=100
X=70
c) X+44=86
X=42
d)X+65=95
X=30

t.3
a) 30-X=12
X=18
b) 25-X= 18
X=7
c) 55-X=22
X=33
d) 100-X=32
X=68

t.4
a) X-18=22
X=40
b) X-18=15
X=33
c) X-55=45
X=100
d) X-89=5
X=94