As you remember, we can represent numbers in a "number line" .
To do this properly we need:
- A point on the line called destination on which we will match the number 0 (zero)
- A unit of measure appropriate.
- a sense of growth, generally from left to right.
Thus, the numbers are split into 3 groups:
- Negatives
- Zero
- Positive
Remember that zero is neither positive nor negative.
ORDER NUMBERS Based on the above we place the numbers from 0 making the right positive and negative to the left.
The far right is a number, the greater this.
absolute value of a number. We call absolute
a number to the distance that is zero.
This amounts to consider the number NO sign.
Thus we have:
The absolute value of (+6) is 6
The absolute value of (-6) is also 6 because they are the same distance from zero. The first left and the second to the right, but the distance is the same and is equal to 6 units.
Opposite number.
opposite numbers call to have the same absolute value but opposite sign.
For example, the (-6) and (+6) are opposites. All numbers
MINUS ZERO have an opposite.
The property is opposite numbers that add up to zero.
This property is extremely useful when solving equations as we shall see.
To add signed numbers is necessary to set both the sign and the absolute value of each of the addends.
SIGNED NUMBERS ADDED
The rules are:
- To add two numbers with the same sign, add the absolute values \u200b\u200band maintaining the sign.
- To add two numbers with different signs, subtract the absolute values \u200b\u200band place the sign of the sum that has greater absolute value.
Examples:
(-4) + (-7) = (-11)
same sign (-4) + (+7) = (+3) different sign
very useful
rely on the number line to understand these rules. The following apllet
can experience. Moving
point A the first term you choose.
Then you move point B to choose the second term. The straight
below you can see the sum.
exercises.
ejercicios_01
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