7th Grade Arithmetic: Math Help for 7th Graders

Arithmetic Help for 7th Graders

When you're doing arithmetic with negative numbers, it helps to have a number line on hand. Your math teacher might have a number line in your classroom, but if not, you can make one yourself. Just draw a horizontal line and mark the center as zero. Then, divide the rest of the line up into small, evenly-spaced segments. Starting from zero and moving to the right, label the segments with the positive numbers. List the negative numbers starting from zero and working to the left. There's no set length that your number line needs to be; but the longer it is, the larger the numbers you can work with.

Adding and Subtracting Integers

Now that you have a number line handy, you're ready to add and subtract integers. Think of each math problem as a set of directions to help you navigate the number line. The first number in the problem is your starting point. The sign in the middle of the problem tells you which direction to go from your starting point. A '+' sign tells to you move to the right on the number line, and a '-' sign tells you to go to the left. The second number in the problem tells you how far to go in that direction.

Let's illustrate this with the problem -9 + 3. Negative nine is our starting point on the number line. From there, the problem tells us to go three spaces to the right. Since negative six is three spaces to the right of negative nine on the number line, -9 + 3 = -6.

Multiplying and Dividing Integers

When you're multiplying and dividing integers, you need to determine whether your answer is positive or negative. A number line won't help you with this task, but these three rules will:

1. If you multiply or divide two integers that have the same sign, then the answer will be positive (2 x 3 = 6 and -6 ÷ -2 = 3).
2. When you multiply or divide two numbers with opposite signs, the answer is negative (2 x -3 = -6 and -6 ÷ 2 = -3).
3. When your multiplication or division problem contains an odd number of negative integers, the answer will be negative (-2 x 3 x 4 = -24). If the problem contains an even number of negative integers, the result will be positive (-2 x -3 x 4 = 24).