‘Think of a Number’ Tricks
Last updated at August 14, 2026 by Teachoo
Transcript
Question 2 - Page 136 Can you come up with more complicated steps that always lead to the same final value? Let's make one up right now that ends in the number 7 Thus, our trick can be Think of a number: x Multiply it by 3: 3x Add 21: 3x + 21 Divide by 3: (3𝑥 + 21)/3 = x + 7 Subtract the original number you thought of: x + 7 – x = 7