Dr. Cotter on Division

Long division used to be considered the ultimate goal of arithmetic. An earlier division algorithm was so complicated it wasn’t taught until college. Even today some students learn a mnemonic in order to remember what to do next. One example is DMSB … [Read more...]

Dr. Cotter on Measurements

Measurement is an application of math that is an important part of everyday life. We measure length, area, volume, mass (weight), temperature, time, angles, and many other attributes. For more than simple comparisons, we need numbers and a basic … [Read more...]

Dr. Cotter on Problem Solving

A few years ago while on a shuttle to speak on math at a convention, I started talking to a young man next to me. When he found out I was involved in math, he said he could solve story problems as long as someone told him what operation to use. The … [Read more...]

Dr. Cotter on Teaching Math

I’d like to take some time to discuss the science and art of teaching math. I call it a science because much research has been done into how children learn in general and especially math. I call it an art because each child is different, requiring … [Read more...]

Dr. Cotter on Addition and Subtraction Facts

Addition  Addition can be thought of as finding the whole when the parts are known. Place value greatly simplifies finding the sum of two numbers. To be efficient in adding, we start with the sums of numbers 1 + 1 through 9 + 9. These are best … [Read more...]

2018 Summer Game #13: On the Number Ten

It is one of those blazing hot, 90º summer days. No one wants to be outside but without air conditioning, inside isn’t much better. My boys’ solution to this dilemma is the nice, cool basement where the computer happens to reside. In my desire to get … [Read more...]