Question

{[( 7- 3) x 5 – 2 + 3 ] : 7 + 9 } : a = 4
a=?

Answer 1

$(((7 - 3) \times 5 - 2 + 3) \div 7 + 9) \div a = 4 \\ ((20 - 2 + 3) \div 7 + 9) \div a = 4 \\ (21 \div 7 + 9) \div a = 4 \\ 12 \div a = 4 \\ a = 12 \div 4 \\ a = 3$