Question

9 subjected from a number gives 21 upon 5 find the number

Answer 1

let the number be x
x-9=21/5
x=21/5+9
x=21+45/5
x=66/5
verification
l.h.s.=x-9
=66/5-9
=66-45/5
=21/5
l.h.s.=r.h.s. proved

Answer 2

x-9 = 21/ 5
x = 21/ 5 +9
x = 21+ 5*9 / 5
x. = 21 + 45 / 5
x = 66 / 5