1.3.1 Comparison of Fractions

1.3.1 COMPARISON OF FRACTIONS

Comparing Fractions

Comparing fractions means determining the larger and the smaller fraction between any two or more fractions.

Comparing Fractions with Same Denominators

When denominators are the same, the fraction with the larger numerator is greater. If both numerator and denominator are equal, the fractions are equal.

Example 1.11

Arrange the following fractions in ascending order: 49, 79, 29, 89

Solution: Ascending order: 29, 49, 79, 89

Comparing Fractions with Unlike Denominators

(I) Using LCM: Convert fractions to like denominators using LCM.

Example 1.12

Which is larger between 47 and 59?

Solution:

LCM of 7 and 9 = 63

4×9=3663 and 5×7=3563

36/63 > 35/63, so 47 is larger.

(II) Using Decimals: Convert fractions to decimals and compare.

Example 1.13

Arrange in descending order: 67, 811, 913, 1115

Solution (decimals): 6/7 = 0.8571, 8/11 = 0.7272, 9/13 = 0.6923, 11/15 = 0.7333 Descending order: 6/7, 11/15, 8/11, 9/13

(III) Using Cross-Multiplication

Example 1.14

Which is larger: 47 or 59?

Cross multiply: 4×9 = 36, 5×7 = 35 → 36 > 35 → 4/7 is larger.

Fraction Battle

Fraction Battle!

Click the fraction that is larger:

Exercise 1.8 - Comparison of Fractions

Exercise 1.8 - Comparing Fractions

1. Arrange the following fractions in descending order

(a) 47, 611, 34, 914

LCM method: Denominators 7,11,4,14 → LCM=308
4/7=176/308, 6/11=168/308, 3/4=231/308, 9/14=198/308
Descending order: 3/4, 9/14, 4/7, 6/11

(b) 56, 79, 23, 67

Cross-multiplication method:
5/6 vs 7/9 → 45>42 → 5/6>7/9
5/6 vs 2/3 → 15>12 → 5/6>2/3
5/6 vs 6/7 → 355/6
6/7 vs 7/9 → 54>49 → 6/7>7/9
7/9 vs 2/3 → 21>18 → 7/9>2/3
Descending order: 6/7, 5/6, 7/9, 2/3

(c) 911, 89, 56, 78

Decimal method:
9/11≈0.818, 8/9≈0.888, 5/6≈0.833, 7/8=0.875
Descending order: 8/9, 7/8, 5/6, 9/11

(d) 37, 511, 613, 917

LCM method: Denominators 7,11,13,17 → LCM=17017
3/7=7307/17017, 5/11=7735/17017, 6/13=7854/17017, 9/17=9009/17017
Descending order: 9/17, 6/13, 5/11, 3/7

2. Arrange the following fractions in ascending order

(a) 23, 67, 58

Cross-multiplication:
2/3 vs 6/7 → 14 2/3 vs 5/8 → 16>15 → 2/3>5/8
Ascending order: 5/8, 2/3, 6/7

(b) 47, 23, 58

LCM method: Denominators 7,3,8 → LCM=168
4/7=96/168, 2/3=112/168, 5/8=105/168
Ascending order: 4/7, 5/8, 2/3

(c) 35, 23, 56

Decimal method:
3/5=0.6, 2/3≈0.6667, 5/6≈0.8333
Ascending order: 3/5, 2/3, 5/6

(d) 25, 13, 58

Cross-multiplication:
2/5 vs 1/3 → 6>5 → 2/5>1/3
2/5 vs 5/8 → 16 Ascending order: 1/3, 2/5, 5/8