Heng Yi
Asked 9 years ago

SG chevron_right Primary 4 chevron_right Number and Algebra

Can someone help me explain this?

Replies 7
Andrew Yap

4=2(1)+2 6=2(2)+2 8=2(3)+2 10=2(4)+2 ... 100=2( )+2?

6 years ago
Heng Yi

Can explain where u get 2 (2) + 2?

6 years ago
Kho Tek Hong

Simply students will see the number pattern: 4, 6, 8, 10, 12, ..,, For Figure 5, the number of pins is 5x2+2. When there are 100 pins, we have 98+2=49x2+2. So there are 49 posters.

6 years ago
Heng Yi

Where do u see the x2?

6 years ago
Kho Tek Hong

5x2 means 5 groups of 2.

6 years ago
Heng Yi

Oic! Thanks

6 years ago
Andrew Yap

You can see that for numbers 4,6,8,10,12,... If one subtract 2 from each number it will be 2,4,6,8,10,... which is 2x1, 2x2, 2x3, and so on. Then add back the 2.

6 years ago

Catherine Koh
Asked 9 years ago

SG chevron_right Primary 5 chevron_right Number and Algebra

Help need for this P5 qns

Replies 6
Andrew Yap

Some remarks: (1) Number of Shaded tiles= pattern square (2) total= (pattern+2) square (3) shaded + white = total

6 years ago
Raymond Ng

6 years ago
Kho Tek Hong

For (a), the number if white tiles is 400-324. For (b), 1156 is the square of 34. So it is Pattern 32. For Pattern 53, the number of shaded tiles is 53^2, the total number of tiles is 55^2, and the number of white tiles is 55^2-53^2.

6 years ago
Catherine Koh

Got it! Thanks all!

6 years ago
Foong Ling

Kho, how to derive at pattern 32?

6 years ago
Kho Tek Hong

The numbers in the first and third columns are square numbers. For example, at row 3, the numbers are 9 and 25, which are respectively 3 squared and 5 squared. 1156 is a number in the third column. It is 34 squared. So it is at row 32.

6 years ago

巧莹 符
Asked 9 years ago

SG chevron_right Primary 5 chevron_right Number and Algebra

Please help with this P5 question too. Thanks!

Replies 4
Judy Lim

10 x 2 = 20 for part i and 20 + 1 = 21 for part ii

6 years ago
Judy Lim

51 - 1 = 50 50/2 = 25

6 years ago
巧莹 符

Thanks, Judy

6 years ago
Judy Lim

👍

6 years ago

巧莹 符
Asked 9 years ago

SG chevron_right Primary 5 chevron_right Number and Algebra

Please help with this P5 question. TIA :)

Replies 4
Judy Lim

Use listing method you should get 12 erasers and 16 pens. 12/3 x 1= $4 36-$4=$32 $32/2=16

6 years ago
Andrew Yap

If all 28 are pens it cost $56 so need to 'transform' some pens to erasers to reduce by $20. For every 3 pens converted to erasers we reduce by $5 so need to covert 12 pens to erasers.

6 years ago
Izam Marwasi

6 years ago
Izam Marwasi

6 years ago

Sherry Chew
Asked 9 years ago

SG chevron_right Primary 4 chevron_right Number and Algebra

One more on P4 qns. Thanks!

Replies 2
Eva Ong

6 years ago
Sherry Chew

Thanks!!

6 years ago

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