Question

11. Put brackets into each of the following expressions to make it correct:

(a) 3+9/5-2x5=20 ​

Answer 1

(3+9)/(5-2)x5 = 20

Explanation:

It's a rather tedious type of task, because there's no simple way to solve them, except kind of by brute force or by trial and error. Here we can start by noticing x5 at the end, so if we can force everything before to be 4 it's gonna be dandy:

can we add brackets to 3+9/5-2 to be equal to 4 (because 20 / 5)?

fortunately, 3+9 is 4 times more than 5-2, so (3+9)/(5-2) = 4

so (3+9)/(5-2)x5=20 is a correct solution