| --- |
| source: ncert |
| topic: arithmetic |
| class_level: class_7 |
| chapter: ch2 |
| difficulty: beginner |
| --- |
| |
| Class 7 | Ch2: Fractions and Decimals |
| Multiplication of fractions: (a/b)×(c/d)=ac/bd. Convert mixed to improper first. |
| 2(3/4)×1(1/3) = (11/4)×(4/3) = 44/12 = 11/3 = 3(2/3). |
| Division: a/b ÷ c/d = a/b × d/c (multiply by RECIPROCAL of second). |
| 3(1/2)÷1(2/3) = (7/2)÷(5/3) = (7/2)×(3/5) = 21/10 = 2.1. |
| Decimal multiplication: count total decimal places. 0.4×0.3=0.12 (1+1=2 places). |
| Division by decimal: 2.4÷0.6 = 24÷6 = 4 (multiply both by 10). |
| Conversion: 0.125=125/1000=1/8. 1.625=1625/1000=13/8=1(5/8). |
| Common mistake: flip SECOND fraction not first when dividing fractions. |
