Muffin Mania

Encourage the students to solve these questions mentally. Materials such as strips of card on a number line could be useful. For example, the following shows that two lots of 3/4 is 1 1/2 and three lots of 3/4 is 2 1/4 .

Alternatively, two lots of 3/4 is 6/4 , and 6/4 is 1 2/4 (or 1 1/2).
If the students don’t know what the word “proportion” means, they could think of it as a fraction (“What fraction of the total is left?”).
The second part of question 2, expressing the proportion as a decimal fraction, may be represented on a double number line:

The number line shows clearly that decimal fractions are numbers that come between consecutive whole numbers (in this instance between 0 and 1).
This may also be represented with Cuisenaire rods, with the orange rod being 1 and each white rod being 1/10 or 0.1. (Thus, six whites would represent 6/10 or 0.6.)
In question 4, the students will have to figure out that 60 muffins is six times more than the number of muffins in the original recipe, so the ingredients will have to be multiplied by 6. Astute students may realise that an easier way is simply to double the results they got for question 3, assuming that these results are accurate.

Answers to Activity

1. 3 1/2 cups plain flour
1 cup castor sugar
3 tsp baking powder
2/3 cup butter
2 eggs
1 1/3 cups milk
grated rind of 2 lemons
3 cups fresh blueberries
2. 16/20 (or 4/5) or 0.8
3. 5 1/4 cups plain flour
1 1/2 cups castor sugar
4 1/2 tsp baking powder
1 cup butter
3 eggs
2 cups milk
grated rind of 3 lemons
4 1/2 cups of fresh blueberries
4. 10 1/2 cups of flour
9 tsp baking powder
2 cups of butter
4 cups of milk