Operations on Real Numbers

Difference

Answer to a subtraction problem

Sum

Answer to an addition problem

Division

For all real numbers a and b (where b =/ 0), a / b = a/b = a * 1/b. That is multiply the first number (the dividend) by the reciprocal of the second number (the divisor).

Subtraction

For all real numbers a and b, a-b = a + (-b). That is, to subtract b from a, add the additive inverse (or opposite) of b to a.

Distance

The distance between two points on a number line is the absolute value of the difference between their coordinates.

Different signs (multiplying real numbers)

The product of two numbers with different signs is negative.

Same sign ( multiplying real numbers)

The product of two numbers with the same sign is positive.

Different Signs ( adding real numbers)

To add numbers with different signs, find the absolute values of the numbers, and subtract the lesser absolute value from the greater. The sum has the same sign as the number with the greater absolute value.

Same Sign ( adding real numbers)

To add two numbers with the same sign, add their absolute values. The sum has the same sign as the given numbers.