# Arithmetic

**Addition** is combining quantities and counting the result. It is learning to express all quantities, in simplest terms and labeling the units accurately.

**Subtraction** is the opposite of addition. Given a quantity, a part is removed and the result is counted and recorded. This is called TAKE AWAY subtraction. Comparing subtraction involves comparing two quantities, counting and recording the difference, for example, the heights of two students.

**Multiplication** is the "short cut" for adding the same quantity over and over. Multiplication facts can be represented by building many piles of the same quantity, making jumps on a number line and building rectangles with the lendge and with the factors. For example, a typical egg cartoon is the rectangular model of the multiplication fact 6 X 2.

**Division** is the opposite of multiplication and there are four ways to think about it. Must students understand "divvy-up" division which is a natural sharing process. Fro example you have 12 cookies to divide between 3 kids. Here you count what is in a pile. The next way is "measuring out" the same quantity over and over. You have 12 cookies and you pass them out two at a time. In this case you count the piles. The third way to think about division is to see the divisor as the number of rows and the quotient as the number of columns. The fourth way is a fraction where the denominator is the divisor and the numerator is the dividend.