Transcript from words to symbols(4)

PROBLEM SOLVING:
FORM WORDS TO
SYMBLOS
LESSON1.1
Keywords that indicate operations used in writing
algebraic expressions.
Operation
ADDITION
keywords
Sum, total, plus,
increased by, more than
SUBTRACTION Difference, exceeds, less
than, less, minus,
decreased by, diminished
by, subtracted from
Keywords that indicate operations used in writing
algebraic expressions.
Operation
keywords
product, multiplied by,
MULTIPLICATION times, twice, doubled,
tripled
DIVISION
Quotient, divided by
How to represent a word expression
by algebraic symbols.
First choose a variable to represent the
unknowns.
 Identify the key word(s) that indicate the
operation.
 Use algebraic symbols to represent the
word expression.

Example 1. Write an algebraic
expression for each word expression.
P29.50 less than the cost of a coat
 Solution:
 Let x = the cost of the coat.


P29.50 less than the cost :
x – 29.50
Example 2. Write an algebraic
expression for each word expression.
Five more than three times the number of
pages
 Solution:
 Let p = the number of pages.


Five more than three times the number :
3p +5
Many word problems involve more
than one unknown .
In these problems, one condition
(CONDITION1) tells how the unknowns
related.
 You can use this condition to represent the
unknowns.
 A second condition (CONDITION 2) tells what

quantities are equal.
 You can use this condition to write an equation
for the problem.
Example 3.

In a recent year, the cost of electricity
used for lighting a house was P9.00
less than 6 times the cost of operating
a color tv set (CONDITION1). The total
cost for these two items was P834.50
(CONDITION 2). Find the cost for
lighting.
Solution
Use CONDITION1 to represent the
unknowns.
 Let c = the cost of operating a color tv
set .
 Then 6c - 9= the cost for lighting.

Solution
Use CONDITION 2  Check:
to write an equation.  CONDITION 1. Is the
 c + 6c - 9= 834.50
cost for lighting
total cost
P9.00 less than 6
 Solve the equation:
times the cost for the
 c + 6c - 9= 834.50
color tv?

7c -9 = 834.50  614.00 =6(P120 –

7c = 843.50
P9.00?

c = 120.50
 Yes.

6c – 9 = 614.00

Solution
Use CONDITION 2  Check:
to write an equation.
 CONDITION 2. Is
 c + 6c - 9= 834.50
the total cost
total cost
P834.50?
 Solve the equation:
 c + 6c - 9= 834.50
 P614.00 + P120 =

7c -9 = 834.50
P834.50?

7c = 843.50

c = 120.50  Yes.

6c – 9 = 614.00

STEPS IN SOLVING WORD
PROBLEMS.
Identify CONDITION1.Use this condition to
represent the unknowns.
 Identify CONDITION2. Use this condition to

write an equation for the problem.
 Solve the equation.
 Check in the original conditions of the problem.
Answer the question.