Percent (Percentage)
ICSE Class 6 · Mathematics · Chapter 16
What this chapter covers
- What percent means
- Percent as a fraction with denominator 100
- Changing fractions and decimals into percent
- Changing percent into fractions and decimals
- Simple problems on percentage
Key definitions
Percent means "out of every hundred", so 30 percent means 30 out of every 100.
The percent sign is the symbol %, and it is written just after the number.
A percentage is an amount written as a number out of 100, using the % sign. "45% of the class came by bus" is a sentence that uses a percentage.
A hundred-square is a big square divided into 100 equal small squares, in 10 rows of 10.
100% means the whole of something, every one of the hundred parts.
Equivalent fractions are fractions that show the same amount, such as (1)/(2) and (50)/(100).
Key points
- Percent means "out of every hundred", and its sign is %.
- A percentage is a fraction with denominator 100: x% means (x)/(100).
- 100% is the whole of something, and 0% is none of it.
- The parts of a whole always add up to 100%.
- To change a fraction into a percentage, make an equivalent fraction with denominator 100.
- To change a decimal into a percentage, write it in hundredths, or move the point two places right.
- To change a percentage into a fraction, write it over 100 and simplify.
- To change a percentage into a decimal, write it in hundredths, or move the point two places left.
- To find a percentage of an amount, change the percentage into a fraction and find that fraction of the amount.
Questions answered
What does 47% mean, in words?
47% means 47 out of every 100.
Write 9% as a fraction with denominator 100.
(9)/(100).
In a hundred-square, 64 small squares are shaded. What percentage is not shaded?
100 - 64 = 36 squares are not shaded, so 36% is not shaded.
Write (3)/(4) and (4)/(25) as percentages.
(3)/(4) = (75)/(100) = 75% and (4)/(25) = (16)/(100) = 16%.
Write 0.72 and 0.3 as percentages.
0.72 = 72% and 0.3 = 0.30 = 30%.
Write 35% as a fraction in its simplest form and as a decimal.
35% = (35)/(100) = (7)/(20), and as a decimal it is 0.35.
Riya wrote 4% as 0.4. Is she right? Explain.
No. 4% is (4)/(100), which is 0.04. The decimal 0.4 means 40%.
Find 20% of ₹450.
20% = (1)/(5), and 450 ÷ 5 = 90, so the answer is ₹90.