This week, I posed to you this question and this sequence of numbers:
“Assume you’re using a basic calculator and you press the numbers in the order shown, replacing each question mark with a mathematical sign. Add, subtract, multiply and divide can each be used only once. What’s the highest number you can possibly get?”
5 ? 4 ? 7 ? 3 ? 2
After the break we’ll take a look at the answer, so click on through!
The key to working this one out is simply logic – you’re aiming for the highest number possible, so everything you do needs to make the end result bigger.
Let’s ignore the order of the sequence for now and look at the numbers and signs: 2, 3, 4, 5, 7 and then +, -, * and /.
To make the biggest number possible, we obviously need to multiply by the largest number. So, *7.
We need to divide by the smallest number, so /2.
We have addition and subtraction left – we add the remaining biggest number and subtract the remaining smallest: +4 and -3 (we can’t use 5 because it’s at the start of the sequence).
Therefore, filling in the blanks, we have 5 + 4 * 7 – 3 / 2 = 30.
So how did you do?