As society grew more complex, measuring became just as important as counting. If a farmer divides a field of wheat among his three children, how much does each get? If a recipe calls for half a cup of ghee, how do we represent that mathematically?
Step-by-step solution
Idea: Whole numbers count whole things. To describe a part of one whole, we write a fraction: the denominator tells how many equal parts the whole is cut into, and the numerator tells how many parts we take.
- The field is one whole shared equally into 3 parts, so each child gets 1 ÷ 3 = 13 of the field.½ mark
- Half a cup means the cup is cut into 2 equal parts and one part is used: 12 cup. Numbers like 13 and 12 are called fractions.½ mark
Check: 13 + 13 + 13 = 1: the three shares make the whole field ✓.
Answer to write in the exam
Field shared equally among 3 ⇒ each gets 1 ÷ 3 = 13 of the field
Half a cup = 12 cup
∴ Parts of a whole are written as fractions: 13 and 12.
Common mistakes that cost marks
- Writing 31 instead of 13: the number of parts (3) goes in the denominator.
- Saying each child gets 3 parts; each gets 1 of the 3 equal parts.
- Writing half as 0.2 instead of 0.5 or 12.
How this can come in the exam
A rope is cut into 8 equal pieces and 3 pieces are used. The fraction of rope used is
- 83
- 38
- 58
- 35
Show answer
(B) 38
3 of 8 equal parts = 38.
A farmer gives 14 of his field to one son and 13 to his daughter. What fraction of the field is left?
Show answer
Given away: 14 + 13 = 312 + 412 = 712 (1 mark). Left: 1 − 712 = 512 (1 mark).Try one yourself
A pizza is shared equally by 5 friends. What fraction does each get, and what fraction do two of them get together?
Show answer
Each gets 15; two together get 25.
More questions like this
- Can you explain why we need q ≠ 0 in the definition of a rational number?
- 1. While adding or subtracting two rational numbers having different denominators, how will you make the denominators equal?
2. Verify the distributive law for rational numbers. - Prove that the following rational numbers are equal:
- Find the sum:
- Find the difference: