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Integer. Whole numbers and their opposites { . . . -3, -2, -1, 0, 1, 2, 3, . . .}. Addition. Same Signs: Add and keep the sign. Different Signs: Subtract and keep the sign of the number with the greater absolute value. Examples of Addition. -4 + 7
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Integer • Whole numbers and their opposites • { . . . -3, -2, -1, 0, 1, 2, 3, . . .}
Addition • Same Signs: • Add and keep the sign. • Different Signs: • Subtract and keep the sign of the number with the greater absolute value.
Examples of Addition • -4 + 7 • Since the signs are different we subtract and keep the sign of the number with the greater absolute value. • 2 + -6 • Same rule as previous problem. • -3 + -4 • Since the signs are the same we add and keep the sign. • -8 + -4 • Same rule as previous problem.
Subtraction • 3 Key Words • Keep, Change, Opposite • Then follow the addition rules.
Subtraction Examples • 8 – 2 • Keep-Change-Opposite makes this problem 8 + (-2) • We now have an addition problem so we must follow those rules. • Since the signs are different we subtract and keep the sign of the number with the greater absolute value. • 4 – (-5) • Keep-Change-Opposite makes this problem 4 + 5 • We now must follow the addition rules. • Since the signs are now the same we add and keep the sign.
More Subtraction Problems 3. 6 – 7 • Keep-Change-Opposite makes this problem 6 + (-7) • We now have an addition problem so we must follow those rules. • Since the signs are different we subtract and keep the sign of the number with the greater absolute value. 4. -4 – (-7) • Keep-Change-Opposite makes this problem -4 +7 • We now have an addition problem so we must follow those rules. • Since the signs are different we subtract and keep the sign of the number with the greater absolute value.
Practice Problems • 9 + (-44) • -19 + (-21) • 15 + (-18) • -72 + 12 • 28 + (-9) • -11 – (-5) • 20 – 6 • -19 – 2 • 16 – (-27) • -14 – (-25)
Multiplication • Same Sign: • Multiply and the answer will ALWAYS be positive. • Different Signs: • Multiply and the answer will ALWAYS be negative.
Multiplication Examples • -2 x -4 • Since the signs are the same we will multiply and the answer will be positive. • -10 x 4 • Since the signs are different we will multiply and the answer will be negative.
Division • Same Sign: • Divide and the answer will ALWAYS be positive. • Different Signs: • Divide and the answer will ALWAYS be negative.
Division Examples • -35 ÷ 7 • Since the signs are different we will divide and the answer will be negative. • -75 ÷ (-5) • Since the signs are the same we will divide and the answer will be positive.