How to Answer 'Show That' Questions in Add Math

A “show that” question hands you the destination: the answer is printed in the question. That changes everything about how you answer it. The marks are entirely for the working that reaches the given result, so the skill is laying out a complete, logical chain, not finding an answer you already have.

Why examiners use “show that”

“Show that” parts do two jobs. They test whether you can construct the derivation, and they protect the rest of the question: because the result is given, a later part can rely on it even if you couldn’t derive it yourself. That’s why you should never abandon a whole question just because the “show that” is hard, the later parts are often still fully answerable.

The rule: show every step

Since the answer is printed, writing it down scores nothing. Every mark is for the working, so the golden rule is show every step, skip nothing. Examiners want to see the logical chain from the given information to the printed result, with no gaps. A step done “in your head” is a step the examiner can’t award.

This is the discipline behind a typical “show that” in calculus or circular measure: state the starting relationship, manipulate it line by line, and arrive explicitly at the given form. Missing even one connecting line, for example not writing the surface-area formula before substituting, forfeits a method mark.

Work toward the given answer, not away from it

Because you know the target, work toward it. If you’re deriving $S = 2\pi r^2 + \frac{2000}{r}$, keep that form in view and steer your algebra to land on it exactly. When your working reaches the printed result, you’ve confirmed you’re right, a built-in check other question types don’t offer.

Don’t use the result to prove itself

One logical trap: in a “show that”, you can’t assume the printed result partway through to justify an earlier step. The argument must flow from the given information to the result, not circularly. Keep the direction clean and the proof is airtight.

“Show that” questions are among the most gettable marks in 0606 once you treat them as working exercises, not answer-hunting. A specialist can show your child exactly how much working earns the marks, that’s part of what the trial class covers. See also how to show working for full marks and command words decoded.