3rd Grade Teaching Strategies

1. Array/Area Model- a set of objects or numbers arranged in order, often in rows and columns. Arrays and area models are different in that an area model is composed of squares that are connected. Multiplication- 3 rows, 5 objects per row Division- 12 objects, 4 groups 3 x 5 = 15 objects 12 ÷ 4 = 3 objects per group

Array

Area Model

2. Bar Model- a visual representation of the information in word problems using bar units.

Addition- Melissa has 50 blue beads and 20 red beads. How many beads does she have altogether? ? 50 + 20 = 70

Subtraction- Ben and Andy have 90 toy cars. Andy has 60 toy cars. How many toy cars does Ben have? 90

90 – 60 = 30

Multiplication- Jack has 3 boxes of cars. There are 8 cars in each box. How many cars does Jack have? ?                                                    8 x 3 = 24

Division- Marcus has 24 pieces of candy. He shares them equally with his 4 friends. How many pieces of candy does each friend get?

24 24 ÷ 4 = 6

50 20

60 ?

8 8 8

? ? ? ?

3rd Grade Teaching Strategies

Two-Step Problem- The soccer club is going on a trip to the water park. The cost of attending the trip is $63. Included in that price is $13 for lunch and the cost of 2 wristbands, one for the morning and one for the afternoon. Write an equation representing the cost of the field trip and determine the price of one wristband.

w w 13 63

3. Base Ten Models- use to model place value of the numbers in your problem.

Addition

Subtraction

4. Equal Groups (shares) - dividing a total number of objects into equal-sized groups. Sharing or grouping things into same sets. Multiplication- 3 flowers, 5 petals per flower Division- 12 stars, 3 groups

3 x 5 = 15 petals 12÷ 3 = 4 stars per group

3rd Grade Teaching Strategies

5. Fact Families- four members are in each fact family. Use fact families to show relationships between addition & subtraction or multiplication & division. When adding, the greatest number is always the sum. When subtracting, the greatest number is always the minuend.

15 + 8 = 23 8 + 15 = 23 23 – 15 = 8 23 – 8 = 15 When multiplying, the greatest number is always the product. When dividing, the greatest number is always the dividend.

7 x 4 = 28 4 x 7 = 28 28 ÷ 7 = 4 28 ÷ 4 = 7

6. Number Bond - shows the relationship in a simple addition, subtraction, multiplication, or

division problem. The number bond is based on the concept of “part-part-whole.”

Addition

+ 25 = 65 + 3 = 68

4 + 3 = 7 43 + 25 = 68

Subtraction

10 –7 = ?

75 – 8 = 67

Multiplication: 7 x 8 = 56 Division: 36 ÷ 9 = ?

43

3 40

8 75 - = 70 – 3 = 67

5 3

3rd Grade Teaching Strategies

7. Place Value - the value of a digit depending on its place in a number. Use place value to find the answers to addition, subtraction, and multiplication problems.

Partial Sums 435 + 515 = (400 + 500) + (30 + 10) + (5 + 5) 900 + 40 + 10 = 950

Partial Differences 57 – 26 = (50 – 20) + (7 – 6) 30 – 1 = 29

Distributive Property 57 x 8 = (50 x 8) + (7 x 8) 400 + 56 = 456

8. Repeated Addition- adding equal amounts until you find the product of a multiplication

problem. Maria has 3 bags of apples. There are 2 apples in each bag. How many apples does she have? Multiplication: 3 x 2 = 6 apples Repeated Addition: 2 + 2 + 2 = 6 apples

9. Repeated Subtraction- subtracting equal amounts until you reach zero. Count the number of times you subtracted to find the quotient of a division problem. Charlie has 18 crayons. He shares them equally with 6 friends. How many crayons does each friend receive?

Division: 18 ÷ 6 = 3 ? crayons Repeated Subtraction: 18 – 6 – 6 – 6 = 0.

Since you subtracted 6 three times before you reached zero, the answer to the division problem is 3 crayons.

10. Rounding- changing a number to a more convenient value. Number Line 0-99 Chart

3rd Grade Teaching Strategies

11. Skip Counting (on a number line)- make equal jumps to solve problems. Multiplication: 3 x 5 = 15 three equal jumps forward from 0 on the number line to 15

Division: 18 ÷ 3 = 6- six equal jumps backwards from 18 on the number line to 0

12. Skip Pattern Counting- when dividing by 2, 3, 5, or 10 skip pattern count by the divisor and stop when you reach the dividend. 21 ÷ 3 =

13. Time On A Number Line Diagram- number line diagrams can be used to solve problems

involving elapsed time. Tony wakes up at 6:45 a.m. It takes him 5 minutes to shower, 15 minutes to get dressed, and 15 minutes to eat breakfast. What time will he be ready for school?

6:30 6:45 7:00 7:15 7:30 7:45 8:00

14. Traditional Algorithm- A set of predefined steps applicable to a class of problems that

gives the correct result in every case when the steps are carried out correctly. Addition With and Without Regrouping Subtraction With and Without Regrouping +1 4 16 4 9 10

243 547 685 567 500 + 436 + 325 - 324 - 385 - 362 679 872 361 182 138

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

5 15 15 7:20

3rd Grade Teaching Strategies

15. Visual Fraction Model- A tape diagram, number line diagram, or area model.

Area Models Number Line

Use visual fraction models to determine if fractions are equivalent.

1 4

1 4

1 4

1 4

1  4  

1  4  

1  4  

   1  4  

1/4 1/4 1/4 1/4