Post on 05-Feb-2016
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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
This should be your result
Rectangular Method for Multiplication (cont.)
2 1 3X 7_______
?
Rectangular Method for Multiplication (cont.)
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
This should be your result
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?
Multiplication Problems
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.
Multiplication Problems
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
Multiplication Problems
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