First, multiply or divide the numbers (don't think about the signs). After that, follow these rules:
1. If you multiply or divide integers with the same signs (positive and positive; negative and negative), the answer will be given the positive sign.
2. If you multiply or divide integers with different signs (positive and negative; negative and positive), the answer will be given the negative sign.
For example:
1. 4 x 4 = +16
2. -9 ÷ 3 = -3
3. -7 x -3 = +21 (or simply 21)
4. 9 ÷ -3 = -3