Lesson 9

Representing Subtraction

Let's subtract signed numbers.

Problem 1

Write each subtraction equation as an addition equation.

  1. \(a-9 = 6\)
  2. \(p-20=\text-30\)
  3. \(z-(\text-12)=15\)
  4. \(x-(\text-7)=\text-10\)

Problem 2

Find each difference. If you get stuck, consider drawing a number line diagram.

  1. \(9 - 4\)

  2. \(4 - 9\)

  3. \(9 - (\text-4)\)

  4. \(\text-9 - (\text-4)\)

  5. \(\text-9 - 4\)

  6. \(4 - (\text-9)\)

  7. \(\text-4 - (\text-9)\)

  8. \(\text-4 - 9\)

Problem 3

Find the solution to each equation mentally.

  1. \(30+a=40\)
  2. \(500+b=200\)
  3. \(\text-1+c=\text-2\)
  4. \(d+3,\!567=0\)

Problem 4

A restaurant bill is $59 and you pay $72. What percentage gratuity did you pay?
 

(From Unit 6, Lesson 7.)

Problem 5

One kilogram is 2.2 pounds. Complete the tables. What is the interpretation of the constant of proportionality in each case?

pounds kilograms
2.2 1
11
5.5
1

______ kilogram per pound

kilograms pounds
1 2.2
7
30
0.5

______ pounds per kilogram

(From Unit 5, Lesson 1.)