The diagram represents the problem. From the quantities given we can work out what 4 units equal, and after that, the total number of children.

Thanks for your help. 😊

Without the boys and girls info the question is solvable at a lower level of difficulty.

Thank you

15 x 7 = 105 5 × 3 = 15

Thks Joanna Lim, is there a way to solve it in model (e.g 2 units for adult n 1 unit for child)

$7+$7+$7+$3=$24 $120/$24=5 Child = 5 Adult = 15

Is ur kid in P3? If yes, tey r currently using the guess & check method

Thks Joanna Lim

Thit Mon Mon Win may I know why $7+$7+$7+$3=$24?

Think of it as ax + by = n then u multiply both sides by 5 to achieve 120.

For this question, it's either Guess and Check or by Supposition. Guess and check is shown above. I shall explain Supposition method. Assume all the 20 people are Adult, cost = 20x$7 = $140. But the total cost is $120. So needed to remove $140-$120 = $20 from the cost. If we convert each adult to children, we just have to remove $4. So $20/$4 = 5. Hence we convert 5 adults to be children. Hence there are 5 children.

Thanks Yueh Mei for sharing the supposition method. I am following the method up to remove $140-$120=$20 from the cost. After that it is quite lost on the part covert each adult to children. In this step, are we using the number of differences to find the number of childrens. For kids, any idea supposition method is normally introduce in primary x? Thanks.

The number of adults being converted to children by removing $4 each. With $20, we would remove $4 each from 5 adults. Hence there are 5 children.

You may practice with assuming all 20 people are children too and see if you can reason the same way and work it out.

For small numbers maybe p3 can handle, bigger numbers probably p4 and above. Importantly, they must understand the reasoning and able to reason it themselves, not memorise the steps. With small numbers, drawing it out helps in the visualisation.

Many thanks Yueh Mei

I think this method works better than the supposition method.

If 46 were boys, 230desks. Difference of 30 desk, with each reducing boy = 2 desks, reduce by 15boys = 30desks. 46-15 = 31boys, 15 girls. Check back (31 x 5) + (15 x 3) = 200 desks.

Thanks for the help!

Besides guess and check, here's a method of supposition. It is beneficial for a student to explore different ways of solving a problem to widen their repertoire of skills.

Guess and check method

Thanks very much for the advice

Remaining 38 boys need to paint extra 3 pcs each = 38 x 3 =114; these 117 pcs are meant to be painted by 2 boys who are absent, therefore each boy is suppose to paint 57 pcs. So total tiles painted = 40 x 57 = 2280 pcs.

Wow.... that's fast and clear. Many thanks folks :)

Thank you very much!

This is which level problem sum pls. Thanks 😊

P5

Lol same

Sa1 season is super stress