Date post: | 18-Nov-2014 |
Category: |
Education |
Upload: | jimmy-keng |
View: | 2,041 times |
Download: | 2 times |
Session W8 Yeap Ban HarWhole Numbers www.banhar.blogspot.comMultiplication & Division
Learning & Reviewing Basic Facts
Some ways to help students acquire and consolidate basic facts.
2 x 4 = 83 x 4 = 8 + 4
2 x 4 = 84 x 4 = 8 + 8
2 x 4 = 85 x 4 = 207 x 8 = 8 + 20
10 x 4 = 40 9 x 4 = 40 – 4
Da Qiao Primary School, Singapore
The product is 48.
She has 6. What
do I have?
Multiplication & Division of Large
Numbers
Some ways to help students make sense of computation algorithm
Find the value of 34 x 2 .
3 4 x 26 0+ 86 8
3 4 x 20 86 06 8
Find the value of 34 x 3 . 3 4
x 39 01 2
3 4 x 31 29 0
The concrete and the visuals help develop meaning i.e. multiplying the tens and ones separately.
3 4 x 39 01 2
The expanded notation emphasizes 34 as 3 tens and 4 ones which are then dealt with separately.
Quantities with different ‘nouns’ are dealt with separately.
Find the value of 28 x 32 .
To see 28 as 20 and 8 and 32 as 30 and 2.
This leads to the idea of (a + b)(c + d).
xUse the digits 0 to 9 no more than once to make a correct multiplication sentence.
The class had four solutions32 x 15 = 48012 x 65 = 78012 x 48 = 57639 x 12 = 468
12 x 43 did not work.
12 can be seen as 10 and 2.Thus, 12 x 65 can also be computed as the sum of 10 x 65 and 2 x 65 i.e. 650 + 130.
12 can be seen as 10 and 2.Thus, 39 x 12 can also be computed as the sum of 39 x 10 and 39 x 2 i.e. 390 + 78.
Alternatively, 40 x 12 can be used to compute 39 x 12.
The use of number bonds to compute large numbers gives students opportunities to develop their number sense.
Find the value of 7081 3 .
Using number bonds, 7081 is 6000, 900, 180 and 1. Each is then divided by three.