"Addition of Rational Numbers" Rational Numbers and Their Operations PPT Courseware (Lesson 2)

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"Addition of Rational Numbers" Rational Numbers and Their Operations PPT Courseware (Lesson 2)

Part One Content: Basic Knowledge Key Points

Knowledge point 1: The operational law of rational number addition

1. Among the following transformations of swapping the positions of the addends, the incorrect one is (D)

A.30+( -20 )=( -20 )+30

B.( -5 )+( -13 )=( -13 )+( -5 )

C.( -37 )+16=16+( -37 )

D.10+( -20 )=20+( -10 )

2. (Original)2/3+( -2.5 )+3.5+("-" 2/3)=[2/3+("-" 2/3)]+[ (-2.5)+3.5], (C) is used in this operation

A. Commutative law of addition

B. Associative law of addition

C. Commutative and associative laws of addition

D. None of the above are correct

3. When calculating 31/4+("-" 2 3/5)+53/4+("-" 8 2/5), the most appropriate arithmetic law is (B)

A.[3 1/4+("-" 2 3/5)]+[5 3/4+("-" 8 2/5)]

B.(3 1/4+5 3/4)+["-" 2 3/5+("-" 8 2/5)]

C.[3 1/4+("-" 8 2/5)]+("-" 2 3/5+5 3/4)

D.("-" 2 3/5+5 3/4)+[3 1/4+("-" 8 2/5)]

Addition of rational numbers PPT, part 2: improvement of comprehensive ability

10. The result of calculating (-2.8)+3+1+(-3)+2.8+(-4) is (B)

A.0 B.-3 C.-8 D.5

11. If a, b, c are three different rational numbers, and a+b+c=0, then the following statement is correct (B)

A. One of the three numbers must be 0

B. If none of the three numbers is 0, it is impossible for them to all have the same sign.

C. There must be two numbers that are opposites of each other

D. There must be two numbers whose sum is equal to the third number

12. Xiaobin purchased 8 sets of children's clothing for 470 yuan and planned to sell them at a certain price. If each set of children's clothing is sold at a price of 60 yuan as the standard price, the excess is recorded as a positive number and the deficiency is recorded as a negative number, then The selling price records of these 8 sets of children's clothing are as follows: +7, -3, -1, -7, -2, +9, 0, +6. When he sells these 8 sets of children's clothing, will he make a profit or a loss? Profit Or how much is the loss?

Addition of rational numbers PPT, the third part: Expanding exploration and breakthroughs

15. A snail starts crawling along a straight line in the east-west direction from a certain point O. It is stipulated that the distance crawling eastward is recorded as a positive number, and the distance crawling westward is recorded as a negative number. The distances crawled are (unit: cm): + 5,-3,+10,-8,-6,+12,-10. Question:

(1) Does the snail finally return to the starting point O?

(2) How far is the snail from the starting point O in centimeters?

(3) During the crawling process, if a sesame seed is rewarded for every 1 cm crawled, how many sesame seeds can the snail get?

Solution: ( 1 )( +5 )+( -3 )+( +10 )+( -8 )+( -6 )+( +12 )+( -10 )=[( +10 )+( -10 )]+[( +5 )+( +12 )]+[( -3 )+( -8 )+( -6 )]=0 +17+( -17 )=0( cm).

So the snail finally returns to the starting point O.

(2) According to the record, the distances of the snail from the starting point O are 5 cm, 2 cm, 12 cm, 4 cm, 2 cm, 10 cm, and 0 cm respectively.

Therefore, the farthest distance the snail can leave from the starting point O is 12 cm.

(3) According to the record, the total distance crawled by the snail is |+5|+|-3|+|+10|+|-8| ;+|-6|+|+12|+|-10|=5+3+10+8+6+12+10=54(cm) ,54×1=54(grains).

So the snail can get 54 sesame seeds.

Keywords: Beijing Normal University edition seventh-grade mathematics PPT courseware free download, addition of rational numbers PPT download, rational numbers and their operations PPT download, .PPT format;

For more information about the PPT courseware "Rational Numbers and Their Operations: Addition of Rational Numbers", please click on the Rational Numbers and Their Operations PPT Addition of Rational Numbers PPT tag.

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Update Time: 2024-10-02

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