Ever wondered how to say exactly how much pizza is left?
Chidi's family orders a pizza cut into 8 equal slices. After dinner, 3 slices are left. "Some pizza" is not exact — but "three-eighths of the pizza" is. That is what fractions are for.
Revision notes
Learn what the top and bottom numbers of a fraction mean, and meet proper, improper and mixed fractions.
Chidi's family orders a pizza cut into 8 equal slices. After dinner, 3 slices are left. "Some pizza" is not exact — but "three-eighths of the pizza" is. That is what fractions are for.
A fraction describes part of a whole that has been cut into equal parts.
The bottom number, the denominator, tells you how many equal parts the whole is cut into. The top number, the numerator, tells you how many of those parts you have.
So 38 means: cut the whole into 8 equal parts and take 3 of them.
🔑 Key idea: Denominator = how many equal parts in the whole. Numerator = how many parts you have.
Share one pizza between 2 people and each gets 12. Share it among 8 people and each gets only 18.
The more parts you cut the whole into, the smaller each part is. So 18 is smaller than 12, even though 8 is bigger than 2.
To find a fraction of an amount, divide by the denominator to get one part, then multiply by the numerator: 34 of ₦800 = ₦800 ÷ 4 × 3 = ₦600.
🔑 Key idea: The parts must be equal — otherwise it is not a fair fraction.
In a proper fraction the numerator is smaller than the denominator, like 38. It is less than one whole.
In an improper fraction the numerator is bigger than (or equal to) the denominator, like 114. It is one whole or more.
We can write 114 as a mixed number: 11 ÷ 4 = 2 remainder 3, so 114 = 234 — two whole pizzas and three quarters of another.
🔑 Key idea: Improper → mixed: divide top by bottom. The remainder stays over the same denominator.
Mr Okafor divides his farm into 4 equal plots. He plants maize on 3 of the plots. What fraction of the farm is not planted with maize?
Step 1: Count the equal parts
The whole has 4 equal parts, so the denominator is 4.
Step 2: Parts not planted with maize
4 − 3 = 1
Fraction = 14
Answer: 14
Ready to check you've got it? Scroll up and work through the lesson: the interactive visuals, practice questions and mastery check are all there.