lesson
Connect three ways of naming an amount
1 · Learn
Per cent means per hundred. 25% is 25/100, which is 0.25 and one quarter. 50% is one half; 20% is one fifth.
The percentage alone does not tell you the actual amount unless you know the whole. 50% of 80 is 40, while 50% of 20 is 10.
Fractions with other useful denominators can become hundredths too. For 2/25, multiply the top and bottom by four: 2/25 = 8/100 = 0.08 = 8%. For 7/20, multiply both by five: 35/100 = 0.35 = 35%. Do not change only the denominator.
2 · Worked example
Two fifths is 40/100, so it is 40% or 0.4. Four fifths is 80% or 0.8.
3 · Your turn
Find 25% of 60 and 40% of 50 using fraction equivalents.
Check your answer
15 and 20. A quarter of 60 is 15; two fifths of 50 is 20.
4 · Apply your learning
Use a hundred grid to connect percentages, decimals and fractions, then apply them to different whole quantities.
Adult guidance and safety
Model the calculation or measurement before relying on a procedure. Explain estimates, units and checks. Use a ruler/protractor and suitable diagrams where needed; text examples alone do not establish practical skill or fluency.
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Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
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