lesson
Updated 6 days ago · 2 views
Imagine you have two hands with 5 fingers each — clap them together and boom, you instantly know you have 10!
Mental math is all about using clever shortcuts so you do not have to count on your fingers one by one.
Fluency relies on Part-Whole Understanding — the ability to rapidly break single-digit numbers into smaller parts (like decomposing 5 into 2+3 or 7 into 6+1) rather than counting by ones.
Double Power
With the Doubles Strategy, you add a number to itself. Committing doubles like 6+6=12 and 8+8=16 to memory gives you reliable anchor points for other calculations.
📊Interactive diagram
When you memorize doubles like 6+6=12 and 8+8=16, you can solve problems in the blink of an eye.
What happens if two numbers are almost twins, but one is just one number bigger?
Near Doubles Strategy
The Near Doubles Strategy helps when adding consecutive numbers (6+7) or numbers with a difference of 2 (6+8).
Link to the known double by doubling the smaller number and adding the difference (6+6+1=13), or doubling the larger number and subtracting (7+7−1=13).
📊Interactive diagram
What if the numbers are not close enough to be doubles, like 8+5?