Question

Simplify: 90 –[70–{80+4-(12–6+2)+3}]

Answer 1

90-[70-{80+4-(12-6+2)+3}]

first we solve parentheses(small) bracket

90-[70-{80+4-8+3}]

now, we solve middle bracket

90-[70-79]

90-(-9)

99