Can't Resist!: Tips, Short-cut... - Mental Math Kids

This is how our brains naturally read, so it feels more intuitive than the "stacking" method. 5. Squaring Numbers Ending in 5 This one makes kids look like absolute geniuses. The Trick: To square a number like 25, 35, or 75: The answer always ends in 25.

At a restaurant, ask them to mentally calculate the 10% or 20% tip before you look at the receipt. Mental Math Kids Can't Resist!: Tips, Short-cut...

Take the first digit and multiply it by the "next" number up. 65 x 65 The end is 25 . The first digit is 6. The next number up is 7. Put them together: 4,225 . How to Make it "Irresistible" This is how our brains naturally read, so

It’s great for any problem involving a 5 or an even number. 4. "Front-End" Addition The Trick: To square a number like 25,

Use physical items like LEGO bricks or Cheerios to show why doubling and halving works.

Round one number to the nearest ten to make it "friendly," solve the problem, and then adjust. Example: For 38 + 25 , turn 38 into 40 (by adding 2). The Math: . Now, take away that extra 2 you added earlier.

It feels like a shortcut that lets them avoid the "old-fashioned" way. 2. Multiplying by 11: The "Split and Sandwich"