Multi-Part Lesson Review
PSI: Work Backward (Lesson 1A)- BASEBALL Last baseball season, Nelson
had four less than twice the number
of hits Marcus had. Nelson had 48 hits.
How many hits did Marcus have last
season? - BANKING Trina had $320 in her savings
account after a withdrawal of $75 and a
deposit of $120. How much did she have
in her account originally?
EXAMPLE 1 A number is divided by 2.
Then 4 is added to the quotient. After
subtracting 3, the result is 18. What is the
number?
Start with the final value and work
backward with each resulting value until
you arrive at the starting value.
18 + 3 = 21 Undo subtracting 3.
21 - 4 = 17 Undo adding 4.
17 · 2 = 34 Undo dividing by 2.Solve One-Step Addition and Subtraction Equations (Lesson 1D)
Solve each equation. Check your solution.- x + 5 = 8 16. r + 8 = 2
- p + 9 = - 4 18. s - 8 = 15
- n - 1 = - 3 20. w - 9 = 28
- b + ^12 = ^34 22. t - ^57 = ^2021
- COOKIES Hector baked some chocolate
chip cookies for himself and his sister.
His sister ate 6 of these cookies. If there
were 18 cookies left, write and solve an
equation to find how many cookies c
Hector baked. - ANIMALS A giraffe is 3.5 meters taller
than a camel. If a giraffe is 5.5 meters tall,
how tall is a camel?
EXAMPLE 2 Solve x + 6 = 4.
x + 6 = 4- 6 = - 6 Subtraction Property of Equality
x = - 2
EXAMPLE 3 Solve y - 3 = - 2.
y - 3 = - 2
+ 3 = + 3 Addition Property of Equality
y = 1EXAMPLE 4
Admission to a popular amusement park
is $8.75 more than the previous year’s
admission price. If this year’s admission
price is $20, write and solve an equation to
find the previous year’s admission.
A + 8.75 = 20 Write the equation.- 8.75 = - 8.75 Subtraction Property of Equality
A = 11.25
So, the previous year’s admission was $11.25.
Addition and Subtraction
EquationsLesson 1Chapter Study Guide and Review 255254_258_C04SGR_895130.indd 255 12/31/09 4:07 PM