Grade 8 Math Book · Counting & Number Sense
Secrets of Mental Math
by Arthur Benjamin and Michael Shermer
"Mathemagician" Arthur Benjamin shares the tricks he uses to do amazing calculations in his head, from quick multiplication and squaring to estimating and memorizing numbers.
Why it's useful
A book that builds number sense and confidence through mental math.
- Why the tricks work. The methods use place value and the distributive property.
- Algebra connections. Squaring tricks connect to (a + b)² and the difference of squares.
- Fun to show off. Students love trying the tricks on friends and family.
Try it in class or at home
- Trick of the week. Teach one trick, like squaring numbers ending in 5.
- Prove it. Use algebra to explain why the trick works.
- Race the calculator. Students challenge a calculator user on easy-trick problems.