Transcript Nutrition for Youth CS255

EQUATIONS
By Teacher Angelo
Can you answer the following?
1. How many hours are there in
1 day?
2. How many grams are there in
1 kilogram?
3. How many satang are there
in 1 Baht?
How will you describe the following?
1 day = 24 hours
1 kilogram = 1,000 grams
100 satang = 1 Baht
14 + 34 = 46 + 2
120 ÷ 6 = 20
Equation – is a mathematical
statement that has two
expressions separated by an
equal sign.
Workbook
Exercise A
Number 1 and 2
on page 27
What can you say about
these equations?
X + 15 = 30
46 - A = 22
D ÷ 8 = 14
Variable is also called
as the unknown which is
any letter from A to Z
Constants are the
numbers being operated
in the expressions.
A–4=2
If A = 4
then 4 – 4 = 0
The equation is
false.
False equation is an
equation that has
expressions of unequal
values on the two sides of
the equal sign.
A–4=2
If A = 6
then 6 – 4 = 2
The equation is
true.
True equation
is an equation that has
expressions of equal
value on both side of the
equal sign.
A–4=2
If A = 6
then 6 – 4 = 2
The equation is true and 6
is the solution to the
equation.
Solution is the value of
the variable that
makes the
equation
true.
Workbook Exercise A
number 5
on page 28
Equality – is the
relationship between two
expressions having the
same value.
Properties of
Equalities
1. Addition Property of
Equality or Symmetric
Property of Addition
– If the same number
is added to each
side of the true
equation, the
equation remains
true
Symmetric Property
of Addition
Example
K – 7 = 16
K – 7 + 7 = 16 + 7
K = 23
2. Subtraction Property
of Equality or Symmetric
Property of Subtraction
- If the same
number is subtracted
from each side of the
true equation, the
equation remains
true.
Symmetric Property
of Subtraction
Example
K + 7 = 16
K + 7 - 7 = 16 - 7
K=9
3. Multiplication property of
equality or Symmetric
Property of Multiplication
- If the same number is
multiplied with each
side of the true
equation, the equation
remains true
Example
4+4=8
(4 + 4) x 2 = 8 x 2
8 x 2 = 16
16 =16
4. Division Property of
equality or Symmeyric
Property of Division
- If each side of the
true equation is
divided by the
same number , the
equation remains
true.
Example
5 + 4 =9
(5 + 4) ÷ 3 = 9 ÷ 3
9÷3=3
3=3
Fill in the blank with the
correct number to make the
equation true.
1.)
(8 + 4) x 3= 12 x _______
2.) (54 – 6) ÷ 12 = 48 ÷ ____
3.) (200 + 15)÷___ = 215 ÷ 5
4.) (152 – 50 )x____ =102 x 4
* TRANSPOSITION
- a process of transposing
number or variable from
one side of the equation
to the other side of the
equation.
EXAMPLE
Solve for the solution of
the equation
B + 8 = 24
Solution
B + 8 = 24
B = 16
-
D - 12 = 35 +
D = 47
C x 4 = 12 ÷
C =3
F ÷ 7 = 9 x
F = 63
Workbook
Exercise A
Number 3 and 4
on page 27 to 28
Writing Equations
Using Equations to
Solve Word
Problems
Example
When 4 is added to Y, the
sum equals 20.Find the value
of Y.
We UNDERSTAND
Question: Find the value of Y.
Information: The number 4 is added to Y and
the sum equals to 20.
Key word:
sum
Mathematical Operation: Addition
We SOLVE
Equation:
Working:
4 + Y = 20
4 + Y = 20
4 – 4 + Y = 20 – 4
Y = 16
We CHECK
By Substitution: 4 + Y = 20
4 + 16 = 20
20 = 20
Answer: The value of Y is 16.
Workbook
Exercise D
Number A to F
on page 33 to 38
Problem number 1:
Chris has a certain amount of
money. He donates 5 Baht to
a temple. He has 25 Baht left
with him now. How much
money does Chris have
initially?
Problem number 2:
Mother buys some donuts and
divides them equally among
five of us. Each of us receives
4 donuts. How many donuts
does Mother buy?
Problem number 3:
A plot of land has an area of a
square kilometers. The land is
divided into 4 equal parcels,
each one with an area of 550
square meters. What is the
area of the original plot of
land?
Problem number 4:
Wendy and Wanee have a
total weight of 67 kilograms.
If Wendy weighs 29
kilograms, what is Wanee’s
weight?
Problem number 5:
8 is subtracted from a
number, Y, then the result is
divided by 4 to obtain a
quotient of 6. What is the
number ,Y?