Juniorcert
No revisions due today
Course Contents (30)
Day 1: Combining Expressions with negative Terms.Description: Subtracting Expressions with a negative term
Objective: The purpose of this module is to practice writing and combining expressions including subtracting expressions with a negative term in it. We find out that subtracing a negative term results in a positive answer.
Help content is :

Subtracting a negative value is like adding that value.

Because we have used integers to show direction like North or South or an increase or a decrease.

  Going -4 miles North is the same as going +4 miles South.

  An increase of   -5 grams is the same as a decrease of 5 grams

 And a DECREASE of -5 grams is the same as an INCREASE of 5 grams.

 

So a SUBTRACTION of -900 grams means the same as ADDING 900 grams.

Combing Expressions with Negative Values

A box weighs (30w -300) grams

A crate weighs 2000 grams

How much does the crate weigh if 3 of these boxes are removed from the crate (in grams)

Answer :

2000 – 3 (30w -300)

= 2000 -90w + 900

= 2900 -90w

We note that when we subtract a multiple of a negative value (in this case subtract 3 times negative 300)

we have -3(-300)

And the result is +900