BillyClue: 72 – 3(42 – 23) x 3
The order of operations is as follows,
1) brackets (that's what they are for!)
2) exponents and roots,
3) division and multiplication
4) addition and substraction
This means, we first need to compute 42-23 = 19
Then we go to the multiplication (is doesnt matter whetter you do 3 x 19 or 19 x 3 first)
This gives 3 x 19 = 57 =>
(do not write =, then you could write 2 = 2 + 1 = 3 which means 2 = 3 while you mean 2 => 2+1 = 3) 57 x 3 = 171
Then finally we have 72 - 171 = -99
+2353 
