Selina Esther Lim
Asked 9 years ago

SG chevron_right Primary 6 chevron_right Number and Algebra

Pls help

Replies 2
Caleb Tey

6 years ago
Xavier Sng

6 years ago

Karen Goh
Asked 9 years ago

SG chevron_right chevron_right

Need help on this Q.is this a work back method?TIA

Replies 8
Jojo Celestino

This is Before & After where in the difference at the beginning is the same as the difference in the end.. The difference will not change since they both spent the same amount of money..

6 years ago
Karen Goh

Jojo Celestino will you be able to show me the working?

6 years ago
Caleb Tey

6 years ago
Jojo Celestino

6 years ago
Karen Goh

Jojo Celestino and Caleb Tey thanks for the working.

6 years ago
Caleb Tey

use Jojo's - his is clearer.

6 years ago
Karen Goh

Caleb Tey tks! I showed my son both methods and he was more comfortable with Jojo method.

6 years ago
Jojo Celestino

No worries.. Glad i am of help.. :)

6 years ago

Adrian Ng
Asked 9 years ago

SG chevron_right Primary 5 chevron_right Number and Algebra

Making it visual...

Replies 3
Xavier Sng

6 years ago
Selina Esther Lim

Thanks both! i got the same answer but wasnt v sure. your illustrations certainly help!

6 years ago
Xavier Sng

Happy to help. Regards.

6 years ago

Selina Esther Lim
Asked 9 years ago

SG chevron_right Primary 5 chevron_right Number and Algebra

Pls help. P5 on percentage / ratio / fraction. Thanks!

Replies 1
Caleb Tey

6 years ago

Allan Chew
Asked 9 years ago

SG chevron_right Primary 3 chevron_right Number and Algebra

Need advise and help to solve this P3 question.

Replies 7
Maggie Lukes

Here's one way to solve this.

6 years ago
Allan Chew

Thanks Maggie. This is very helpful.

6 years ago
Xavier Sng

Explanation: If all forty notes were $2-notes, the total amount of money would have been $80. Since the actual total amount of money is $146, there are $(146 - 80) = $66 to account for. One needs to "convert" a $2-note into a $5-not with $3 and since there are 22 times $3 in $66, it reasons that there are twenty-two $5-notes and eighteen $2-notes. 

6 years ago
Xavier Sng

Shown working : (146 - 2 x 40) / (5 - 2) = 22 Thus 40 - 22 = 18 (Ans)

6 years ago
Izam Marwasi

Xavier Sng.. Nice and clear explanation...

6 years ago
Raymond Ng

6 years ago
Xavier Sng

Thank you, Izam Marwasi. Raymond Ng's method is the same but derives from forty $5-notes. It does eliminate one step as there is no need to subtract the number of $5-notes from the total.

6 years ago

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