Mathematical operations there are four types: addition, subtraction, multiplication, and division. Therefore, examples of the cons will be four types. Negative numbers within the example brackets in order not to confuse the mathematical operation. For example, 6-(-7), 5+(-9), -4*(-3) or 34:(-17).
Addition. This action may take the form of:1) 3+(-6)=3-6=-3. Replacement steps: first disclosed the brackets, the + sign changes to the opposite, then from the larger (in absolute value) of the number "6" is subtracted least - "3", then the answer will receive a mark greater, that is "-".
2) -3+6=3. This example can be recorded differently ("6-3") or to decide on the principle of "from greater to take less and to give the answer the sign more."
3) -3+(-6)=-3-6=-9. When opening brackets are replaced operations of addition subtraction, then summarizes the modules of the numbers and results put a minus sign.
Subtraction.1) 8-(-5)=8+5=13. Disclosed brackets, the sign of the action is reversed, it turns out the addition.
2) -9-3=-12. Sample elements are summarized and an overall "- "sign.
3) -10-(-5)=-10+5=-5. When opening brackets again changed the sign to "+", then from the larger number subtracted from smaller and have the answer - the sign of the larger number.
Multiplication and division.When performing multiplication or division sign doesn't affect the action itself. If you work or divide numbers with different signs the answer is assigned a minus sign, if the numbers with the same signs, the result is always the sign "plus".1)-4*9=-36; -6:2=-3.
2)6*(-5)=-30; 45:(-5)=-9.
3)-7*(-8)=56; -44:(-11)=4.