Maths · KS3 Y7 · Ratio & Proportion

Percentage as a proportion

Percentage as a proportionFree8:14Heddy Score 3 of 7, below the standard

What you need to know

  • In reverse percentage questions, treat the original amount as 100%.
  • After an increase of 15% the new amount is 115% of the original; after a decrease of 20% it is 80%.
  • Divide the given amount by its percentage to find 1%, then multiply by 100 to get the original.
  • If you are given the size of the change, divide it by the percentage change to find 1%.
  • Lay out the working clearly so an examiner can follow each step.

In this clip

0:05–7:46The unitary method
Also coversPercentage as a proportion
Heddy Score3/7, Below the standard
See the seven stars
  • Trusted source · passed. The creator's own upload, live and playable here.
  • On the map · not judged yet. A teacher watched it: it mainly teaches this map topic.
  • Spec-true · not judged yet. Accurate, and right for the current UK specification.
  • Focused · passed. One idea, short enough to watch in one go.
  • Accessible · passed. Good captions, clear sound and pictures.
  • Safe for children · not judged yet. Right for 11 to 16 year olds, with no sales pitch.
  • Proven · not judged yet. Earned from our students: they learn from it, find it helpful and watch it to the end.
★ passed · ☆ pending · ✕ failed
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Our own students' answers. These are what move ★7 Proven.
On YouTube

467K views · 7.84K likes · Cognito 1.37M subscribers

As reported by YouTube on 2026-11-02. Not part of the Heddy Score.
How the Heddy Score works

Why we picked it

Builds every reverse percentage question on the same find-1%-first idea, a clean application of the unitary method.

Cognito on YouTubechecked 2026-10-22

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