Question 9 - Figure it out - Page 73 - Chapter 4 Class 7 - Another Peek beyond the Point (Ganita Prakash II)

Transcript

Question 9 In which of the following multiplications is the product less than 1? Can you find the answer without actually doing the multiplications? (a) 7 × 0.6 (b) 0.7 × 0.6 (c) 0.7 × 6 (d) 0.07 × 0.06The rule we follow here is If you multiply two numbers that are both smaller than 1 (like 0.5 or 0.7), the answer will always be smaller than 1 Let’s check each part now (a) 7 × 0.6: No (7 is a whole number, result is 4.2) (b) 0.7 × 0.6: Yes (Both are less than 1. 7 × 6 = 42, with 2 decimals → 0.42) (c) 0.7 × 6: No (6 is a whole number, result is 4.2) (d) 0.07 × 0.06: Yes (Both are less than 1. 7 × 6 = 42, with 2 + 2 = 4 decimals → 0.0042) (d) 0.07 × 0.06: Yes (Both are less than 1. 7 × 6 = 42, with 2 + 2 = 4 decimals → 0.0042) Thus, products in (b) and (d) are less than 1. We found this without full multiplication by noticing that in both cases, we are multiplying a decimal part by another decimal part.