Toán Tếng anh: Số hữu tỉ

Week 1 
Period 1 §1. RATIONAL NUMBERS 
I/ Objectives: 
- The knowledge: Students will know the concept of rational numbers 
- The skills: Students will know how represent the rational numbers on a number 
line and compare two rational numbers. The relationships between sets numbers N 
 Z Q. Students have skills presenting Math solutions in English well 
- The attitude: The first students have reason, anlysis and observe. 
II/ Vocabulary: 
- Rational numbers: Số hữu tỉ 
III/ Teaching and students aids: Book, notebook, tool 
IV/ Content: 
 1/ Class organization: 
- Greeting 
- Checking attendance: How many students are absent on today ? 
2/ Introduced: 
In this chapter, we shall extend the number system further. We shall introduce the 
concept of rational numbers along with their addition, subtraction, multiplication and 
division operations 
3/ New lesson: 
Teachers activities Students activities Content 
Introduce, In grade 6 we 
known: the equivalent 
fractions are represent the 
same part of a whole. The 
numbers are rational 
numbers. Suppose we have: 
3, -0,5, 0, 2
5
7
. We can 
write:Therefore: 3, -0,5, 
0, 2
5
7
 are rational numbers 
Thus: What are rational 
numbers ? 
Why the numbers 0,6, -1,25, 
2
1
3
 are rational numbers ? 
Is the integer a rational 
number ? Why ? 
In the same with integers. 
Let us represent the rational 
numbers on a number line 
We divide the length 
Look and write down 
Read 
The students explain 
Answer: The integer is a 
rational number. Because a 
can be written a = a/1 
A student represents on the 
board 
Look and write 
1/ Rational numbers: 
A rational number is 
defined as a number that 
can expressed in the from 
a/b. Where a and b are 
integers and b # 0. ( 
a,b Z,b 0 ) 
The set rational numbers 
are sign: Q 
? 1 Why do the numbers 
0,6, -1,25, 2
1
3
 are rational 
numbers ? 
? 2 
The integer a is rational 
number 
2/ Rational numbers on a 
number line: 
? 3 Represent the number 
integers: -1, 1, 2 on a 
Q 
Z 
N 
>
-1 10
5
4
>
-1 10
2
3

between 0 and 2 into 8 
equal parts and show five 
parts as 5/4 in the Fig.1 
Write 2/-3 = -2/3 ( The 
denominator is positive 
integer ) 
In the same example above. 
We divide the length 
between 0 and -1 into 3 
equal parts and show two 
parts as -2/3 th the Fig.2 
Who can compare ? 
Hit: Find least common 
multiple ( LCM ) of 3 and 5 
Who’s can remark for your 
friend ? 
Give remark to the student’s 
answers 
Introduce the example 1,2 
Slove the following 
problem 
A student represents on the 
board 
Read the statements above 
and write down on the 
notebook 
number line 
Example 1: We want to 
show 5/4 on a number line 
Fig.1 
Example 2: We want to 
show 2/-3 on a number line 
Fig.2 
- On the number line, a 
point show the rational 
number x is call point x 
3. Comparion of rational 
numbers 
? 4 Compare -2/3 and 4/-5 
( or -2/3 and -4/5 ) 
Give two any rational 
number x, y, we get always: 
x = y, x y 
Example 1: Compare: -0,6 
and 1/-2 
Solution: -0,6 = -6/10; -1/2 
= -5/10 
Because -6 0 
then -0,6 < 1/-2 
Example 2: Compare: -3
1
2
and 0 
Solution: -3
1
2
 = 
7
2
; o = 
0
2
Because -7 > 0 and 2 > 0 
then -7/2 < 0/2 
- If x < y then on the 
number line. The rational 
number x on the left 
rational number y 
- Rational number less than 
0 is negative rational 
number 
- Rational number great 
than 0 is positive rational 
number 
Who can ? 
In each of the following 
numbers, which number is 
postive rational number, 
negative rational number, 
neither a negative rational 
number nor a postive 
rationasl number. 
Who can remark for your 
friend ? 
Give remark to the student’s 
answers 
A student represents on the 
board 
- The number 0 ( zero ) is 
neither a negative rational 
nmuber nor a positive 
rational number. 
? 5 
Postive rationnal numbers: 
2/3, -3/-5 
Negartive rational numbers: 
-3/7, 1/-5, -4 
Neithes a negative rational 
number nor a postive 
rationasl number: 0/-2 
 4/ Consolidation: 
Exercise: Who can do it ? 
1/7: Fill appropriate sign ( , , ) in the box 
- 3 N; -3 Z, -3 Q, -2/3 Z, -2/3 Q, N Z Q 
3/8: Compare rational numbers 
 a/ 2/-7 and -3/11 
 b/ -213/300 and 18/-25 
 c/ -0,75 and -3/4 
5/ Homework: 
- Review all the exercise that we do today 
- Solve the following exercise 2/7; 4,5/8