Distance Education Mini-Lesson,
Module 5
Mary C. Fanchette
TEC 571 Grand Canyon University
Instructor:
March 23, 2011
Objective: TLWBAT solve algebraic addition and
subtraction equations by applying the inverse
operation and substitution to check solutions.
Standard: 6-3.5 Use inverse operations to solve
one-step equations that have whole-number
solutions and variables with whole-number
coefficients.
What: Solve addition and subtraction equations
Why: To find the unknown value and to master the
foundation skills for Algebra
How: Using inverse operations and substitution to
check solutions
Let's Think!
When you were in elementary school, you
learned about things called "fact
families". Can you still find the missing
members of these "fact families"?
1. _____ + 7 = 10
2. _____ - 5 = 3
3. _____ x 8 = 24
4. _____ ÷ 4 = 3
Deeper Thinking....
Can you solve these?
1. x + 7 = 10
2. n - 5 = 3
3. m x 8 = 24
4. s ÷ 4 = 3
Do they look similar to the "Fact
Families" that you just solved? What do
you think the letters represent?
Algebra: a language of symbols, including
variables.
Variables - Review
variable - a letter that stands for a number
6 + m = 13
18 ÷ p = 9
7t = 35
z - 8 =3
Words to know:
Equation: a mathematical statement that has
numbers, at least one variable, and an equals
sign. An equation is balanced, like a scale.
Evaluate: To solve, to find the value of
Inverse operations: Operations that undo
each other, opposite: addition/subtraction,
multiplication/division
Solution: the value of a variable that makes
the equation true or balanced.
Are you ready?
Algebra
Equation Inverse
Choose the best term from the list to complete each
sentence.
1. An ________ has numbers, variables, an equal sign
and at least one operation.
2. Operations that "undo" each other are called
________________________.
3. _____________ is a language of symbols, including
variables.
Inverse Operations
1. What is the inverse of multiplication?
2. What is the inverse of subtraction?
3. What is the inverse of addition?
4. What is the inverse of division?
Solving Addition and
Subtraction Equations
The "How To" for solving equations:
1. Identify the operation taking place.
2. Solve by performing the inverse
operation on both sides of the equal
sign to keep the equation balanced.
3. Check your answer by substituting
the value you found in the place of the
variable.
A Question of Balance
The two sides of an equation are equal to each other.
The left side and the right side must be balanced.
6+4
=
10
When you do something to one side of an equation, you
have to do the same thing to the other side.
Quick Video to help out...
http://studyjams.scholastic.com
/studyjams/jams/math/algebra/a
dd-sub-equations.htm
Together… We Do!
1) k + 24 = 45
2) n - 15 = 40
3) 4 = x - 12
4) 10 = y + 6
5) 7 + n = 18
6) t - 9 = 23
On Your Own… You Do!
1) 21 + x = 63
2) s - 7 = 12
3) a + 6 = 11
4) 24 = y -13
5) m - 5 = 16
6) 100 = w + 75
Checking for Understanding…
Let's see if you can
answer some
questions about
algebra and
equations....
Number your
whiteboards 1-5.