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Maths · Fractions, decimals and percentages

Convert decimal and percentage

Convert one decimal to or from a percentage.

Free to use and free to share. There is no sign-up, no score, and nothing a child does here is recorded or sent anywhere.

Practise it now

Drive the bar to 38, then work out the same amount as a percentage.

This exercise practises convert decimal and percentage alongside its own main skill, Converting Fractions to Percentages.

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A worked example

One question of the kind this skill is tested with, worked all the way through: the reasoning, and what the wrong answers are there to catch.

From 0.15 to a percentage

Write 0.15 as a percentage.

The bar shows 3 of its 20 equal parts shaded, which is 0.15 of it and therefore 15% of it.

  • A bar cut into 20 equal parts, with 3 of them shaded.
  1. 15%
  2. 150%
  3. 3%
  4. 0.15%

Answer: 15%

How you get there

0.15 of the whole is 15 hundredths, because multiplying by 100 moves the point two places and not one, so 0.15 is 15%.

Why the other answers tempt

Adding a % sign to the decimal does not convert it.

If they are stuck, say this

A percentage counts hundredths, so ask how many hundredths are in 0.15 before you write the % sign.

Now do it live in Triple Track

What this exercise is doing

Triple Track

Drive the bar to 38, then work out the same amount as a percentage.

This engine’s own main skill is Converting Fractions to Percentages. It practises convert decimal and percentage alongside it.

38 shades 3 of the 8 pieces of the bar. Dividing 3 by 8 gives exactly 0.375, and "per cent" just means "out of a hundred", so multiplying by 100 gives 37.5%. The three lanes stop at the same place on the board because they are not three amounts: they are one amount written three ways. Nothing was rounded anywhere - 3 divided by 8 stops dead after three decimal places.

  1. Step 1. Line them up. Drag any lane. Land all three on 38 and watch the other two follow.
  2. Step 2. Under the flap. Two lanes are covered. 38 is what percentage?

What to say if they get stuck

  1. Drag any lane and all three move together - they are one amount wearing three names.
  2. 38 means the whole is cut into 8 equal pieces and you take 3.
  3. Per cent means "out of a hundred". Fill the hundred square and count the cells.

Open Triple Track on its own page to share it

What usually goes wrong here

  • Drops or adds the percent sign without scaling by one hundred.

This is the wrong answer 11+ papers are built to offer, so it is worth watching for directly: a child who does this will look confident and still lose the mark. If it keeps happening on convert decimal and percentage, the fix is the misunderstanding rather than more questions.

Where convert decimal and percentage sits in the 11+

The 11+ does not test these skills in isolation, and practising one in the wrong order wastes the practice. These are the skills the curriculum map connects this one to.

Secure this first

Convert fraction and decimal

Decimal equivalence supports percentage conversion.

The same thinking carries into

Locate an equivalent value

Symbolic equivalence transfers to number-line placement.

How convert decimal and percentage differs from the skills beside it

The same exercise practises several skills, and telling them apart is often the difficulty rather than the exercise itself. On this page the skill is: convert one decimal to or from a percentage, and it stops where excludes finding a percentage of a quantity.

Related maths skills

All maths 11+ skills

Questions parents ask about convert decimal and percentage

Answered from what the skill map records about this skill, not from a template. Every answer here is on the page, and the same questions are the page's FAQ structured data.

Convert one decimal to or from a percentage. It is one of 55 named maths skills in the 11+, in the fractions, decimals and percentages strand, and this page carries 1 interactive exercise that practises it.

Convert decimal and percentage rests on something else being secure first

This skill depends on convert fraction and decimal. A free diagnostic checks those alongside every other maths skill, so you find out whether the problem is here or underneath it.