Ratio GCSE lesson: simplifying, sharing in a ratio and bar models

Ratio: practice

Draw the bar for each one, then find one box first. The stretch is optional.

Diagnostic question: choose and explain

1. Amir and Beth share money in the ratio 3 : 5. Beth gets £12 more than Amir. How much does Amir get?
   1. £4.50
   2. £36
   3. £18
   4. £30

Practice questions

1. In its simplest form, 12 : 18 = ___ : ___
2. Share £48 in the ratio 3 : 5. The larger share is £___
3. A 35 cm ribbon is cut into two pieces in the ratio 2 : 5, the shorter piece on the left. The line measures the ribbon in cm from its left end. Drag the marker to where the cut goes.They drag a marker on a number line from 0 to 35.
4. Ella and Finn share a pizza in the ratio 2 : 3. The pizza is cut into 10 equal slices. Shade Ella's share.They shade parts of a circle cut into 10 equal parts.
5. Don't answer these yet. For each one, is the number you are given the total, one share or the difference?They sort 6 items into The total and One share and The difference.
6. Red and blue counters are in the ratio 2 : 7. What fraction of the counters are red?
   1. 2/7
   2. 2/9
   3. 7/9
   4. 5/9
7. Paint is mixed blue : yellow = 2 : 3. A painter uses 12 litres of yellow. She makes ___ litres of paint in all.
8. 63 sweets are shared in the ratio 2 : 3 : 4. The largest share has ___ more sweets than the smallest.
9. Stretch: in a club, boys : girls = 3 : 4. Then 6 more boys join, and now there are as many boys as girls. How many girls are in the club?

Support: For question 7: draw blue 2 boxes and yellow 3 boxes. The 12 litres of yellow cover 3 boxes, so find one box first, then count every box.

Ratio: exit

Draw the bar first. One or two sentences for the second question.

1. Cara and Dan share some money in the ratio 4 : 1. Cara gets £30 more than Dan. They share £___ in all.
2. Describe your bar for the first question: how many boxes each person has, and which boxes the £30 covers.

Exit check

One difference problem and its bar show who finds one box from the right boxes.

Cara and Dan share money in the ratio 4 : 1, and Cara gets £30 more. Students draw the bar, find the total and say which boxes the £30 covers.

Ratio: bars and boxes

Draw a bar model for questions 2 to 6. Say whether you are given the total, one share or the difference, and find one box first. Check each answer against every fact in the question.