Operations with Integers

Learn adding signed numbers, multiplying signed numbers.

Lesson 2 of 32 parts Practice Flashcards

1/2

Adding Signed Numbers

Objective: Explain adding signed numbers, apply the stated method, and check its conditions.

To add signed integers, combine directed changes. Equal signs add magnitudes and keep the sign; opposite signs subtract magnitudes and use the sign of the larger magnitude. Subtracting a number is equivalent to adding its opposite. Subtracting a negative adds its positive opposite.

Formulas

$x−y=x+(−y)$

Worked examples

Try itEvaluate −7+7.Show answer

Step 1: The addends have opposite signs. Step 2: Subtract the magnitudes and keep the sign of the larger magnitude. Step 3: The result is 0.

Swipe sideways to move between sections

Adding Signed Numbers

Objective: Explain adding signed numbers, apply the stated method, and check its conditions.

Formulas

$x−y=x+(−y)$

Worked examples

Try itEvaluate −7+7.Show answer

Step 1: The addends have opposite signs. Step 2: Subtract the magnitudes and keep the sign of the larger magnitude. Step 3: The result is 0.

Multiplying Signed Numbers

Objective: Explain multiplying signed numbers, apply the stated method, and check its conditions.

Two factors with the same sign have a positive product; different signs give a negative product. Multiply absolute values to determine magnitude. These sign rules also apply to division by a nonzero integer; division by zero is undefined. The sign rule does not make division by zero valid.

Formulas

$(−a)(−b)=ab; (−a)b=−ab$

Worked examples

Try itEvaluate (−6)(−7).Show answer

Step 1: Two negative factors have a positive product. Step 2: Multiply magnitudes 6·7. Step 3: The result is 42.

You finished the reading!

Lock it in with a few practice questions, then move on to the next lesson.

Practice Next lesson

Previous lessonPositive and Negative Numbers Next lessonFractions Decimals and Rational Numbers