Doubling & Halving Game

Doubling & Halving Quiz/Game
In this game, your goal is to use the Doubling & Halving strategy as a mental math shortcut used to simplify multiplication. By doubling one factor and halving the other, you create a new equation that has the exact same product but is much easier to solve in your head. Scroll down the page for a more detailed explanation.

 

 

How to play the Doubling & Halving Game

1. Choose Your Training Level
   Apprentice Level (Easy): You will only practice multiplying even numbers by 5. This is the perfect “entry-level” shortcut because doubling 5 always gives you 10, and multiplying by 10 is easy—you just add a zero.
   Example: 14 × 5
   Halve the even number: 14 ÷ 2 = 7
   Double the other number: 5 × 2 = 10
   New Problem: 7 × 10 = 70
   
   Titan Level (Hard): You will tackle trickier numbers like 15, 25, and decimals (like 3.5). The logic is the same, but the numbers require a bit more focus.
   Problem: 16 × 3.5
   Halve 16: 8
   Double 3.5: 7
   New Problem: 8 × 7 = 56
   

2. When the problem appears (e.g., 16 × 5):
   Halve the first number: Look at the left number and divide it by 2. (Type 8 in the first box).
   Double the second number: Look at the right number and multiply it by 2. (Type 10 in the second box).
   

3. Finish the Math
   Now that you’ve turned 16 × 5 into 8 × 10, type the final answer (80) in the total box and hit “Check Shortcut."
   

In the harder mode, you are looking for patterns like:

If you see…	Change to…
14 × 15	7 × 30
12 × 25	6 × 50
18 × 3.5	9 × 7

This video gives a clear, step-by-step approach to learn doubling & halving multiplication strategy.

• Show Video

 

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