Question

12+(20+30)-2
4+6+(45-5)
65-30+(20-10)
(97-7)-(35-5)

Answer 1

1) 12+(20+30)-2=(12+50)-2=62-2=60

2)4+6+(45-5)=10+40=50

3)65-30+(20-10)=35+10=45

4)(97-7)-(35-5)=90-30=60