Multiplication Whole Numbers II: Part 2 of 2

Multiplication Whole Numbers II:Part 2 of 2

Teacher’s Quality Grant

Benchmark

• MA.4.A.1.1 Use and describe various models for multiplication in problem-solving situations, and demonstrate recall of basic multiplication and related division facts with ease.

• MA.4.A.1.2 Multiply multi-digit whole numbers through four digits fluently, demonstrating understanding of the standard algorithm, and checking for reasonableness of results, including solving real-world problems.

Traditional Method

2 1 3X 3 3 2_______

2X3=62X1=22X2=4

3X3=93X1=33X2=6

3X3=93X1=33X2=6

4 2 66 3 9

6 3 9___________+

7 0 7 1 6

Slide the results over 1 significant place to the left

Slide the results over 2 significant places to the left

Regular Addition

Multiplication by Partitioning

2 1 3X 7_______

?

Multiplication by Partitioning

2 1 3X 7_______

1491

200 X 7 = 1400

10 X 7 = 70

3 X 7 = 21

14007021+_______

1491

Regular Addition

Partition the number in its significant digits and multiply

Add the results of the previous multiplications

This should be your result

Rectangular Method for Multiplication

2 4 5X 3_______

?

Rectangular Method for Multiplication (cont.)

245 X 3 245 X 003Mach the number of digits by adding zero if necessary

2 X4 5

0

3

0

0

0

0

0

0

0

00

0

00

0

0 1 16 2 5

7 3 5

2 4 5X 3

7 3 5_______

Add diagonally

Add diagonally

Add diagonally



2 1 3X 7_______

?


213 X 7 213 X 007Mach the number of digits by adding zero if necessary

2 X1 3

0

7

0

0

0

0

0

0

0

00

0

00

0

1 0 24 7 1

4 9 1

2 1 3X 7

1 4 9 1_______

Add

diagonally

Add

diagonally

Add

diagonally


1

Add

diagonally

Other Multiplication Methods

2 1 3X 3 3 2_______

?

Triple-Digit Multiplication

• Three-digit multiplied by a one-digit number (no carrying):123 x 3 = ?(1) 3 x 3 = 9 (the ones)(2) 2 x 3 = 6 (the tens)(3) 1 x 3 = 3 (the hundreds)Answer: 123 x 3 = 369

Triple-Digit Multiplication• Three-digit number multiplied by a two-digit number (no carrying):

424 x 12 = ?First Part (424 x 2):(1) 4 x 2 = 8(2) 2 x 2 = 4(3) 4 x 2 = 8Answer: 424 x 2 = 848

Second Part (424 x 1):(1) 4 x 1 = 4(2) 2 x 1 = 2(3) 4 x 1 = 4Answer: 424 x 1 = 424

Third Part (848 + 4240 -- We added the zero):848 + 4240 = 5,088

Triple-Digit Multiplication• Three-digit number multiplied by a three-digit number (no carrying):

213 x 332 = ?First Part (213 x 2):(1) 2 x 2 = 4(2) 1 x 2 = 2(3) 3 x 2 = 6Answer: 213 x 2 = 426

Second Part (213 x 3):(1) 2 x 3 = 6(2) 1 x 3 = 3(3) 3 x 3 = 9Answer: 213 x 1 = 639

Third Part (213 x 3):(1) 2 x 3 = 6(2) 1 x 3 = 3(3) 3 x 3 = 9Answer: 213 x 1 = 639

Third Part (426 + 6390 + 63900 -- We added the zeros):426 + 6390 + 63900 = 70,716

Multiplication Problem

• Utilize all of the already explained multiplication methods to solve the problems presented in the next slide:

Examples of methods:• Traditional method• Partitioning method• Rectangular method

Multiplication Problems

524X 23_______

?

185X 268

?_______

134X 4_______

?

Word Problems

• Gather in groups of 2 and discuss the best strategy to solve the following word problems

Word Problem 1

• Mommy bought four egg cartons, and each had six eggs. Two of the eggs were bad. How many good eggs did Mommy get?

Word Problem 2

• A museum sells bricks with inscribed names. A plaza brick costs $200.00 and a walkway brick costs $100.00. Suppose 7 plaza bricks and 12 walkway bricks are sold. How much more money is made on the plaza bricks than on the walkway bricks?


In the following slides the highlighted column on the right, displays the total for each row. The highlighted row on the bottom, displays the total for each column. Fill in the missing boxes to complete the puzzle. All missing numbers are between 0 and 9.


6 9 6 1 2 6487 7 3 2 6 17646 9 9 4 5 97206 5 5 2 3 9009 9 3 6 5 7290

13608 25515 2430 96 900


4 3 1 3 7 2526 8 6 3 2 17283 4 3 3 8 8645 5 7 3 2 10501 3 7 3 9 567

360 1440 882 243 2016

Multiplication Whole Numbers II: Part 2 of 2

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