"Extension of the law of addition of integers to decimals" Addition and subtraction of decimals PPT

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"Extension of the law of addition of integers to decimals" Addition and subtraction of decimals PPT

Part One: Review Import

Calculate it as easily as possible.

72＋42＋28＋158

357-85-15

The commutative law of addition, the associative law of addition and the properties of subtraction are used.

What laws of operation were applied in the calculation?

Commutative law of addition: a+b=b+a

Additive associative law: a+b+c=a+(b+c)

Properties of subtraction: a-b-c=a-(b+c)

The law of addition of integers is extended to decimals PPT, part two: exploring new knowledge

Are the results on both sides of each set of equations below equal?

3.2＋0.5 0.5＋3.2

(4.7+2.6)+7.4 4.7+ (2.6+7.4)

The commutative and associative laws of addition of integers also apply to the addition of decimals.

Applying the laws of operations can make some decimal calculations easier.

Calculate 0.6+7.91+3.4+0.09.

How are you going to calculate it?

I count from left to right.

0.6＋7.91＋3.4＋0.09

Calculate 0.6+7.91+3.4+0.09.

This is how I calculated it.

How are you going to calculate it?

The law of addition of integers is extended to decimals PPT, the third part: consolidation exercises

1. Fill in the appropriate number in □.

(1) 6.7＋4.95＋3.3 = 6.7＋□+4.95

This calculation applies the commutative law of addition.

(2) (1.38 + 1.75) + 0.25

＝＋（＋）

This calculation applies the additive associative law.

2. Calculate the following questions as easily as possible.

1.88＋2.3＋3.7

4.02-3.5+0.98

The law of addition of integers is extended to decimals PPT, Part 4 content: Class summary

In the mixed operations of the four decimal arithmetic, we must carefully observe the characteristics of each number, pay attention to the relationship between numbers and the operation symbols in front of each number, and appropriately use the commutative law of addition, associative law and the operational properties of subtraction to perform simple operations. First add and subtract two or more numbers that can be "rounded".

The law of addition of integers is extended to decimals PPT, part 5: homework

1. Log in to query and download "Classwork Design".

2. Related exercises in the exercise book.

Keywords: Free download of PPT courseware for mathematics in the second volume of the fourth grade of the People's Education Press, extension of the law of addition of integers to decimals PPT download, download of addition and subtraction of decimals PPT, .PPT format;

For more information about the PPT courseware "The addition and subtraction of decimals, the law of addition of integers is extended to decimals", please click the Addition and Subtraction of Decimals PPT, the law of addition of integers is extended to decimals PPT tag.

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Update Time: 2024-09-07

This template belongs to Mathematics courseware People's Education Press Fourth Grade Mathematics Volume 2 industry PPT template

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