When You Forget the Formula: The Power of "Guess and Check" in Maths — Selective online test papers & screen-based prep

It's Not Cheating, It's Strategy In school, teachers often say, "Show your working, don't just guess." In the Selective Test, getting the right answer is all that matters. Sometimes, the algebra required to solve a question is too hard for Year 6. That's when you use Systematic Guess and Check (or Back-Solving).

How it Works Question: A father is 4 times as old as his son. In 20 years, he will be twice as old. How old is the son? Instead of writing complex equations: Look at the answers: A) 8, B) 10, C) 12, D) 15. Test B (10): If Son is 10, Dad is 40 (4×). Add 20 years: Son becomes 30. Dad becomes 60. Check the rule: Is 60 twice as much as 30? Yes. Answer: B.

Why Start with B or C? If you test "C" and the number is too big, you know the answer must be A or B. You save time by eliminating half the options instantly.