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I.E.S. “Andrés de Vandelvira” - Sección Europea

Mathematics

If the number is positive, the absolute value is the same number. If the number is negative, the absolute value is the opposite. The absolute value of a number is always a positive number (or zero). We specify the absolute value of a number n by writing n in between two vertical bars: |n|. Exercise 3 Plot on the number line and after order them from less to great. -2

+8

0

-5

3

5.2 Adding Integers Rules for addition:

When adding integers with the same sign: We add their absolute values, and give the result the same sign. With the opposite signs:

We take their absolute values, subtract the smaller from the larger, and give the result the sign of the integer with the larger absolute value.

5.3 Subtracting Integers Rules for subtraction:

Subtracting an integer is the same as adding the opposite. We convert the subtracted integer to its opposite, and add the two integers. The result of subtracting two integers could be positive or negative. Exercise 4 Calculate operating first the expressions into brackets. a) 8 − (3 − 2 + 5)

b) 87 − 4 − 9) + (2 + 3 − 1)

c) (2 − 7) − (5 − 4) − (1 − 6)

d) (2 + 4 − 1) − (7 − 4 − 9)

e) − (1 − 2 + 3 − 7) + (3 − 4) − (2 − 3 − 5)

Exercise 5 Remove brackets and calculate: a) 8 − (3 − 2 + 5)

b) 87 − 4 − 9) + (2 + 3 − 1)

c) (2 − 7) − (5 − 4) − (1 − 6)

d) (2 + 4 − 1) − (7 − 4 − 9)

1-7

Maths 2º eso  

Libro creado para los alumnos de 2º eso de Matemáticas en inglés para aquellos IES que tienen sección Europea

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