"Oral Calculation of Adding and Subtracting Two-Digit Numbers" PPT on Addition and Subtraction Within Ten Thousands

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"Oral Calculation of Adding and Subtracting Two-Digit Numbers" PPT on Addition and Subtraction Within Ten Thousands

Part One: Learning Objectives

1. Enable students to master the calculation method of adding and subtracting two-digit numbers orally, and be able to perform oral arithmetic correctly. Cultivate students' oral arithmetic skills and problem-solving abilities.

2. Experience the process of exploring two-digit oral arithmetic methods, experience the diversity of algorithms, cultivate students' diversified problem-solving methods, and improve the flexibility of thinking. Able to discover mathematical problems from life, organize and analyze data, and solve practical problems. Enhance students' awareness of applying the knowledge they have learned to life and their awareness of innovation.

[Learning Key Points]

1. Perform oral calculations of addition and subtraction of two-digit numbers correctly, and learn how to add and subtract two-digit numbers orally.

2. Be able to choose appropriate problem-solving methods according to specific situations.

[Difficulties in learning]

Develop students' computing skills and problem-solving skills.

Oral calculation of two-digit numbers, addition and subtraction of two-digit numbers PPT, Part 2: Reviewing the past and learning the new

think about it

(1) How much does a toy duck and a bear cost in total?

35＋34＝

Calculate first: 35+30=65

Calculate again: 65+4=69

(2) How much does a toy piano and a car cost in total?

39＋44＝

Calculate first: 39+40=79

Calculate again: 79+4=83

Oral calculation of two-digit numbers, addition and subtraction of two-digit numbers PPT, Part 3: Classroom exercises

1. Fill in the blanks.

(1) When the numbers in the ones digit add up to ( ), carry 1 to the ( ) digit; when the numbers in the tens digit add up to ( ), carry 1 to the ( ) digit.

(2) To subtract two digits from a two-digit number, start with the () digit.

【Answer】

Ten, ten, ten, hundred; pieces

【Analysis】

(1) This question tests carry and addition: "The numbers in the ones place add up to ten, and advance 1 to the tens place. The numbers in the tens place add up to ten, and advance 1 to the hundreds place."

(2) To subtract two digits from a two-digit number, start with the ones digit.

2. Select .

(1) 35+34�34+35, the symbol to be filled in � is ( ).

A． >

B． <

C． =

(2) Which of the following two items has the price closest to 30 yuan? ( )and( )

A. Badminton 4 yuan

B. Hat 8 yuan

C. Basketball 25 yuan

3. Calculate.

22+20= 45+10= 33+40= 18+20=

22+23= 45+13= 33+43= 18+22=

Oral calculation of two-digit numbers, addition and subtraction of two-digit numbers PPT, Part 4: Summary

Oral calculation method

First use two digits to add a whole ten, then add one digit.

First add whole tens to whole tens, add single digits to single digits, and then add the resulting sums.

How to calculate two-digit numbers orally and subtract two-digit numbers

①First subtract an integer from a two-digit number, and then subtract a one-digit number from the difference.

② First subtract the whole tens from the whole tens, subtract the single digits from the single digits, and then add the differences obtained twice.

③Think of the vertical pose and calculate the number mentally.

Oral calculation of two-digit numbers, addition and subtraction of two-digit numbers PPT, Part 5: Consolidation after class

1. Which of the following expressions is correct ( ).

A.25+70=95(meter)

B.70-25=45 (meter)

C.70-25=35(meter)

2. Xiao Hong and Xiao Ming went fishing. Xiao Hong caught 17 fish and Xiao Ming caught 24 fish. How many fish did Xiao Ming and Xiao Hong catch in total?

【Answer】

17+24=41 (bar)

Answer: Xiao Ming and Xiao Hong caught 41 fish in total.

【Analysis】

This question should add up the fish caught by Xiao Ming and Xiao Hong.

3. There are 72 candies in the cup. If 38 candies are taken away, how many candies are left in the cup?

【Answer】

72-38=34 (pieces)

Answer: There are 34 candies in the cup.

【Analysis】

Calculate according to the formula in the question, and don’t forget the units.

Keywords: free download of PPT courseware for third-grade mathematics from the People's Education Press, download of oral arithmetic two-digit addition and subtraction of two-digit PPT, download of addition and subtraction within ten thousand PPT, .PPT format;

For more information about the PPT courseware "Addition and Subtraction Within Ten Thousand, Oral Calculation of Two-Digit Numbers, Adding and Subtracting Two-Digit Numbers" PPT courseware, please click the Addition and Subtraction Within Ten Thousand, Oral Calculation of Two-Digit Numbers, Adding and Subtracting Two-Digit PPT Courseware.

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Update Time: 2024-11-24

This template belongs to Mathematics courseware People's Education Press Third Grade Mathematics Volume 1 industry PPT template

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