# Another Mental Subtraction Method

This free math video shows another way to do mental subtraction. Basically, in subtraction problems you can add or subtract the same amount to both numbers without changing the difference. Cuisenaire Rods prove this to be true in a visual and kinesthetic way. It is always best to show children (and adults) WHY a rule works instead of just telling them the rule.

# Introduction to Ratios

Cuisenaire Rods provide a concrete way to talk about the concept of ratios. The “I get, you get” idea comes from Crewton Ramone’s House of Math – lots of great ideas there!

Using manipulatives to teach complex math concepts will bring a wider range of children to understanding than the traditional formula-driven way of teaching. Children with visual and kinesthetic learning styles will especially benefit from this style of instruction.

The significance of understanding whether an answer is going to be odd or even is not often instantly understood. If children understand this, they will have an instant way to know whether their answer may be wrong. They will know that 459+243 has to be even because they are both odd numbers. It develops numbers sense. That’s a good thing!

After watching this free math video, I see how I could have done things a little better. Writing all even numbers in red and odd numbers in black would have helped tie in the Cuisenaire Rods to the symbols. Our numerals themselves show no similarity to quantities (what does the shape of a 5 have to do with five things?) so bridging that gap with colors or letters to indicate odd or even would be a good idea.