Maths homework help!

[VividImagination]

Can someone please help with ds3’s homework.

Question
The ratio of a catering tin of baked beans to a regular tin is 5:2.
A catering tin weighs 2KG.
Calculate the weight of a regular tin in grams.

How does he show the working for this?

Divide by five and multiply by two.

2000 ÷ 5 = 400g then 400 × 2 = 800.

Often schools use the oz method so you would draw 5bkocks to represent a catering tin and 2 for a regular tin. Since we know the five blocks of the catering tin equals 2kg we divide by 5 to work out how much each block is worth. So we know each block is worth 400g (or 0.4kg).the regular tin has two blocks so we need to multiply 400g by 2 to calculate the total in a regular tin. This method works for all the different ways ratio problems can be posed.

I think the first step is showing understanding of how many grams in 1kg.

so 2kg = 2000g

then the rest of Opies layout.

Thank you.

Dh is the mathematician in this house but he’s not very patient at explaining things. I can work it out on my head but am no use at knowing how to write it down. So thank you all .

This won't show very well online, but my preferred method for a ratio question is a table

catering...…………...regular
5...………………………..2
2000g...……………….X

Then see what you have to multiply 5 by to get to 2000 (ans 400), shown by a curved arrow going from the 5 to the 2000 labelled x400.
Then draw a similar curved arrow going from the 2 to the X including the label.
Finally do the calculation 2x400 = 800g

The table method continues to work beautifully clearly all the way up to GCSE grade 6 level questions. It can be expanded to have a 'Total' column and as many other regular columns as needed.

Thank you. That’s very helpful. Some of the questions showed tables but I didn’t look too closely as he seemed to know what to do with those ones. He’s my third. You would think I’d have mastered it by now!