Addition Equations
51 = 47 + b
b = 4
a - 15 = 3
a = 18
Solve:
350 = 140r
r = 2.5
Solve:
x/17 = 3
x = 51
2/3 + x = 3/4
x = 1/12
4 = c - 26
c = 30
Solve:
1/5k = 15
Solve:
12.9 = n/10
n = 129
Write a real-world problem that could be represented by the equation:
z + 2 = 9
Check Answers.
Write a real-world problem that could be represented by the equation.
x - 12 = 20
Check Answers.
8x = 96
Write a real-world problem that can be represented by each equation:
n/21 = 6
Check Answers
Define a variable, write an equation, solve the equation, use substitution to check your answer.
Lee is 32 years younger than his mother and his mother is 67 years old. How old is Lee?
let x = Lee's age
Lee's age + 32 = 67
x + 32 = 67
x = 35
35 + 32 = 67; 67 = 67
Define a variable, write an equation, solve the equation, use substitution to check your answer.
Terry is hiking on the trail to Mt. LeConte in the Great Smoky Mountains. He has hiked 2.1 miles and has 4.5 left before he reaches the summit. How many miles long is the hike?
let x = length of hike
length of hike − 2.1 = 4.5
x − 2.1 = 4.5
x = 6.6
6.6 − 2.1 = 4.5; 4.5 = 4.5
Define a variable, write an equation, solve the equation, use substitution to check your answer.
The Houston Rockets scored 66 points in the second half. There are 24 minutes in a half. What was their average number of points per minute?
let x = number of points per minute
24x = 66
x = 2.75
24(2.75) = 66; 66 = 66
Define a variable, write an equation, solve the equation, use substitution to check your answer.
The average American composted about 1.5 pounds of trash per day. How many pounds would the average American compost in 90 days?
let x = pounds composted in 90 days
x/90=1.5
x = 135
135/90=1.5;1.5=1.5
Define a variable, write an equation, solve the equation, use substitution to check your answer.
Mt. McKinley in Alaska is 20,320 feet high. It is 9,081 feet higher than Mt. Hood in Oregon. How tall is Mt. Hood?
let x = height of Mt. Hood
height of Mt. Hood + 9,081 = 20,320
x + 9,081 = 20,320
x = 11,239
11,239 + 9,081 = 20,320; 20,320 = 20,320
Define a variable, write an equation, solve the equation, use substitution to check your answer.
Elroy is taking a train to downtown. The train has made 11 stops already and will make another 23 stops before it reaches its destination. How many total stops are there on the train route?
let x = number of train stops
x − 11 = 23
x = 34
34 − 11 = 23; 23 = 23
Define a variable, write an equation, solve the equation, use substitution to check your answer.
Gold costs $1,654 per ounce. How many ounces are needed to be worth $16,540?
let x = number of ounces
1,654x = 16,540
x = 10
1,654(10) = 16,540; 16,540 = 16,540
Define a variable, write an equation, solve the equation, use substitution to check your answer.
Zita wants to buy an MP3 player that is on sale for 25% off. The original price of the MP3 player was $200. What is the amount of the discount?
let x = amount of discount
x/0.25=200
x = 50
50/0.25=200;200=200