"Subtraction of Rational Numbers" PPT courseware

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"Subtraction of Rational Numbers" PPT courseware

Question 1: The highest temperature in Hohhot in one day is 19 ℃, and the lowest temperature is 7 ℃. What is the temperature difference in Hohhot during this day? How to calculate?

Question 2: The highest temperature in Xiamen is 9 ℃ and the highest temperature in Harbin is -7 ℃. How many degrees Celsius is the highest temperature in Xiamen higher than the highest temperature in Harbin on this day? How can it be calculated?

Question 3: The highest temperature in Harbin is -7℃ and the lowest temperature is -12℃. What is the temperature difference in Harbin today? How did you calculate it?

Method 1: It can be seen from the figure that 9-(-7)=16

Method 2: According to the fact that subtraction is the inverse operation of addition, from (-7)+16=9, we also get 9-(-7)=16

Calculate the following equations:

50-20＝__________, 50＋(-20)＝＿＿＿＿;

50-10=__________, 50+(-10)=___________;

50-0＝___________, 50＋0＝＿＿＿＿＿＿;

50-(-10)=______, 50＋10＝＿＿＿＿＿;

50－(－20)＝＿＿＿，50＋20＝_＿＿＿＿＿.

What conclusion can you draw by comparing the two equations in each row?

subtraction rule for rational numbers

Subtracting a number is equal to adding the opposite of that number

a-b＝a＋(-b)

Example 1. Calculate the following questions:

(1)5-(-5) (2)0-7-5

(3)(-1.3)-(-2.1) (4)11/3-21/2

Solution: (1)5-(-5)=5 + 5= 10

(2)0-7-5=0+(-7)+(-5)=-7+(-5)=-12

(3)(-1.3)-(-2.1)=(-1.3)+2.1=2.1-1.3=0.8

Practice in class:

1. Oral calculation:

(1)3-5＝＿＿; (2)3-(-5)＝＿＿;

(3)(-3)-5=_____; (4)(-3)-(-5)=____;

(5)-6-(-6)＝____; (6)-7-0＝＿＿;

(7)0-(-7)＝_____; (8)(-6)-6＝____;

(9)9-(-11)＝＿＿;

1. It is known that the sum of a number and 3 is -10, find this number.

2. fill in the blank

⑴-9＋( )＝16; ⑵42＋( )＝-25;

⑶( )-(-18)＝35; ⑷( )-87＝-21

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"Subtraction of Rational Numbers" Rational Numbers and Their Operations PPT Courseware 2:

"Subtraction of Rational Numbers" Rational Numbers and Their Operations PPT Courseware 2 The highest temperature in Urumqi is 4 degrees, and the lowest temperature is 3 degrees (1) What is the temperature difference in Urumqi today? List the equations. Tip: Since subtraction is the inverse operation of addition, 4 - (-3) is required..

"Subtraction of Rational Numbers" Rational numbers and their operations PPT courseware:

"Subtraction of Rational Numbers" Rational Numbers and Their Operations PPT Courseware Review Calculation (1) 4 + 16= (2) (2) + (27) = (3) (9) + 10 = (4) 45 + (60) = ( 5) (7) + 7 = (6) 16 + 0 = (7) 0 + (8) = (1) ..

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Update Time: 2024-09-11

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