How to see it
A fraction is equal parts of a whole. The bottom number, the denominator, says how many equal parts the whole is cut into. The top number, the numerator, says how many of them we have. Cut a pizza into eight equal slices and the slices are small. Cut it into five and the slices are bigger. So one fifth is bigger than one eighth. The more parts, the smaller each part.
A worked example
What is three eighths of 40? Divide by the bottom to find one part: 40 divided by 8 is 5. Then take the number of parts you want, 3. Three fives are 15.
The common mistake: thinking a bigger denominator means a bigger fraction
The trap is "eight is bigger than five, so one eighth is bigger". That compares the digits, not the slices. Also check the parts are equal: a circle cut into unequal pieces is not in eighths.
Try one
Two fifths of 35.
- A7
- B14
- C10
- D17.5
Show the answerHide the answer
Right: B, 14
35 divided by 5 is 7, two sevens are 14.