CBSE Class 8 Mathematics Question 2 of 11

Algebra Play — Question 2

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Question
Can you come up with more complicated steps that always lead to the same final value?
Answer

Yes. Here is an example. We can understand such tricks through algebra. Step 1: Think of a number = x Step 2. 5 times it = 5x Step 3: Add 25 = 5x + 25 Step 4: Divide by 5 = \(\frac{5 x+25}{5}\) = x + 5 Step 5: Subtract the original number you thought of (x + 5) – x = 5 For Example: Consider a number 18. 5 times 18 = 90 Add 25 = 90 + 25 = 115 Divide by 5 = 115 ÷ 5 = 23 ∴ 23 – 18 = 5 Math Talk (Page 137)