Grade 3 Mathematics Addition and Subtraction PDF

Mathematics for Grade 3, Part 1, People's Education Press Addition and subtraction 4 within 10,000 (II) 1 Addition Lesson 2 Adding three-digit numbers (non-continuous carry)  Review introduction 1...

Mathematics for Grade 3, Part 1, People's Education Press Addition and subtraction 4 within 10,000 (II) 1 Addition Lesson 2 Adding three-digit numbers (non-continuous carry)  Review introduction 1. Perform vertical calculations. 234+265= 499 471+318= 789 234 471 + 265 + 318 499 789 2. 625 pots 286 pots 358 pots of roses Chrysanthemum orchid （ 1 ） How many pots of chrysanthemums and roses are there in total? 625+358=(620+350)+(5+8)=983(pots) （ 2 ） How many pots of chrysanthemums and orchids are there in total? 625+286=(620+280)+(5+6)=911(pots) Students, can you use the vertical method to calculate?  Target presentation 1. Master the calculation method of adding three-digit numbers (one-time carry) and be able to calculate correctly. 2. Experience the formation process of the calculation method of adding three-digit numbers to three-digit numbers and cultivate the ability of transfer and analogy. 3. Cultivate the values ​of protecting and loving wild animals. Self-directed learning 2 How many kinds of birds and mammals are there in my country's 271+31= Number wetlands? of Group species What does the birds 271 question require? reptiles 122 Can you write a mammals formula based on the 31 information in the table? Expression Practice Method 1: Mental Arithmetic 271+31= 302(kinds ) 271 + 31= Classmates, let’s 270 1 30+1 270+1 30 1 discuss the method of mental arithmetic together. 300 + 2 = 302 Method 2: Vertical Column Students, do you 271+31= know how to write the vertical form? hu ten one ndr s s 2 7 1 ed + 3 1 How do you write 7+3=10 in the tens 2 place? Method 2: Vertical Column 271+31= 302(kinds ) hu ndr ten s one s 7 + 3 = 10 2 7 1 ed ten one s s + 3 1 1 0 3 2 When the tens place reaches ten, add one to the hundreds place.  271+31= 302(kinds ) 1 2 7 1 + 3 1 3 0 2 Answer: There are 302 species of birds and mammals in my country's wetlands.  Think about 271+903 ， How to calculate? this: 2 + 9 = 11 Tho u san Hun dred ten s ones What to do if the tens one s 0d 2 7 1 sum of hundreds is tens? 1 1 + 9 0 3 The hundredth place is 7 4 eleven(1ten+1ones), so add 1(ten) to the thousandth place. Think about 271+903 ， How to calculate? this: The number in the tho hun thousandth place is: usa dre ten ones s 1 nd d 0 +1 = 1 0 2 7 1 Do not forget + 9 0 3 to add the 1 in the hundredth 1 1 7 4 place. Summa ry Kind tips When calculating addition in vertical form, you should not only pay attention to aligning the same digits, but also be careful not to miss the carry 1. Group discussion: What should we pay attention to when calculating addition within ten thousand? Align the same If the sum of the numbers is digits and add them tens, then move 1 to the starting from the previous digit. 。 ones digit. Consolidation Exercises Calculate in vertical form. 365+825= 1190 719+252= 971 1 1 365 719 + 825 + 252 1190 971 281+64= 345 65+93= 158 1 281 65 + 64 + 93 345 158  Expanded Application 1. Fill in the blanks. Mom wants to go to the supermarket to buy a pressure cooker for $350, an electric rice cooker for $218, and a water purifier for $523. 1100 Mom should take about $( ). 2. When a careless kid was doing an addition problem, he accidentally mistook the 3 in the ones position for 8 and the 7 in the tens position for 1. The sum he got was 736. What should the correct sum be? The difference between the wrong number and the original number: 73−18=55 Correct and: 736+55=791 Answer: The correct sum should be 791.  Class summary Ones, tens, and hundred bits must be aligned; Start from the ones position; If the sum of the digits is tens or more (2 digit number), write down the digit at one’s place and carry over 1 to the left place digits and add. CLASS IS OVER!