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India
Class VI

Adjacent signs

Lesson

Just Give Me a Sign

In some questions that involve negative numbers, you'll see that two operators, or mathematical signs, might be written together.

There are some rules to follow to make sure you always use the right operation:

Remember!
  • A negative sign and a positive sign [$+$+($-$) or $-$($+$+)] becomes a negative [$-]$]
  • Two negatives [$-$($-$)] become a positive [$+]$+]

Examples

question 1

Evaluate: $4-\left(-5\right)$4(5)

Think: Two negative signs become a positive.

Do:

$4-\left(-5\right)$4(5) $=$= $4+5$4+5
  $=$= $9$9

 

question 2

Evaluate: $-9+\left(-6\right)$9+(6)

Think: A positive and a negative sign together become a negative.

Do:

$-9+\left(-6\right)$9+(6) $=$= $-9-6$96
  $=$= $-15$15

 

question 3

Evaluate: $4+\left(-10\right)$4+(10)

Think: A positive and a negative sign together become a negative.

Do:

$4+\left(-10\right)$4+(10) $=$= $4-10$410
  $=$= $-6$6

 

Careful!

The two negative signs have to be right next to each other.

 

$-4-8$48 means "$-4$4 minus $8$8." This does not become a positive.

$-4-\left(-8\right)$4(8) means "$-4$4 minus $-8$8" This becomes "$-4$4 plus $8$8." In this case, the operators changed.

The same rules apply, even when there are more than $2$2 numbers.

Examples

question 4

Evaluate: $18+\left(-7\right)-\left(-12\right)$18+(7)(12)

Think: A positive and a negative sign together become a negative and two negative signs together become a positive.

Do:

$18+\left(-7\right)-\left(-12\right)$18+(7)(12) $=$= $18-7+12$187+12
  $=$= $23$23

 

QUeSTION 5

Evaluate: $-7-\left(-2\right)-\left(-6\right)$7(2)(6)

QUESTION 6

Evaluate: $9+\left(-8\right)$9+(8)

QUESTION 7

Evaluate: $-14-\left(-16\right)$14(16)

 

Outcomes

6.NS.NMI.2

Identification of integers on the number line, operation of addition and subtraction of integers, showing the operations on the number line (addition of negative integer reduces the value of the number) comparison of integers, ordering of integers.

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