Food portions

Is it a good idea to use measuring spoons or measuring cups to measure a large amount of flour?

Would you rather have $\frac{1}{2}$  of a 10 cm chocolate bar or $\frac{1}{2}$  of a 4 cm chocolate bar? Explain your choice.

What fraction statements can you say about the following image? There is a 6-pack egg carton missing an egg and the other 6-pack egg carton has only one egg in it.

Imagine a pizza you have eaten. Create different fractions around how a pizza can be cut. How do they compare?

Think about and brainstorm everyday examples of fraction terms such as half and a quarter. (Example: a quarter is the name of the coin that represents $\frac{1}{4}$  of a dollar.)

Access the following Homework Zone video “Comparing Fractions,” where Teacher Shahana tells you more about fractions.

What new learning happened after exploring this video?

Fractions

A fraction simply represents a number. The denominator tells how many equal parts are in the whole or set. The numerator tells how many of those parts you're talking about. Fractions can be used in four ways:

• You can use a fraction to show parts of a whole. For example, if a cake is cut into 8 slices and you eat 2 slices, then there are $\frac{6}{8}$  of the cake left over.
• You can use a fraction to name part of a collection of things. For example, if you have a dozen donuts, 7 chocolate, 3 strawberry and 2 vanilla. $\frac{7}{12}$  are chocolate flavour, $\frac{3}{12}$  are strawberry flavour and $\frac{2}{12}$  are vanilla flavour.
• You can use a fraction to show how to equally share. For example, if 4 students are sharing 6 brownies they will need to separate the brownies evenly. You might do this by giving each person 1 brownie. Next, separate the remaining 2 brownies into $\frac{1}{2}$  pieces and each person would get another $\frac{1}{2}$ . In total, each student would receive 1 $\frac{1}{2}$  brownies.
• You can use a fraction to enlarge or shrink a quantity. For example, if students are exploring what $\frac{1}{3}$  of a set of 6 marbles might be, they would discover that $\frac{1}{3}$  of 6 equals 2.

Equivalent fractions show the same amount but are divided into a different number of portions. You can use equivalent fractions to add, subtract and compare fractions. To find equivalent fractions you can multiply or divide the numerator and the denominator by the same number other than zero. Using manipulatives (for example, a number line, area model or set model) can you show how $\frac{4}{6}$  and $\frac{2}{3}$  are equal? Fractions must have a common denominator before adding and subtracting, therefore making equivalents is important. Common denominators are also helpful when comparing fractions.

An improper fraction is a fraction with a numerator greater than its denominator. This means the fraction is larger than a whole. For example, $\frac{13}{5}$ , $\frac{9}{4}$  and $\frac{3}{2}$  are improper fractions.

A mixed number is fraction with a combination of whole numbers and fractions of a whole. For example, 1$\frac{1}{2}$  and 2$\frac{3}{4}$  are mixed number fractions.

Adding and subtracting with fraction strips and number lines

Fraction strips and number lines are handy tools to help you add and subtract fractions.

You can use the following fraction strips or number lines to help you solve the questions.

Solve the following problems independently or with a partner using fraction strips and/or number lines, where possible.

1. Example: The recipe for a cheese sauce requires $\frac{1}{3}$  cup of flour at the beginning and another $\frac{1}{8}$  cup of flour as the sauce is cooking. How much flour is required?

   • Solution

     $\frac{1}{3}+\frac{1}{8}=$ 

     First, find a common denominator. Both 3 and 8 are factors of 24. So, multiply the numerator and denominator by the same number.

     $\frac{1}{3}\times \frac{8}{8}=\frac{8}{24}$ 

     $\frac{1}{8}\times \frac{3}{3}=\frac{3}{24}$ 

     So,

     $\frac{8}{24}+\frac{3}{24}=\frac{11}{24}$ 

     Therefore, $\frac{11}{24}$  of a cup of flour is required for the cheese sauce.

2. Jane baked the muffins for $\frac{1}{4}$  of an hour on high and then another $\frac{1}{3}$  of an hour on a lower temperature. How long were the muffins in the oven total?
3. Jerome is making a shepherd’s pie. It asks for 1 cup of mashed potatoes. He put $\frac{5}{7}$  of a cup in the bowl. How much more mashed potatoes does he need to add to the recipe?
4. This morning at the bakery, $\frac{1}{5}$  of the customers bought donuts and $\frac{1}{20}$  of the customers bought bagels. The rest just purchased a coffee. What fraction of the customers bought just coffee?
5. Jana has three measuring cups full of sugar: $\frac{1}{3}$  cup, $\frac{1}{4}$  cup, and $\frac{1}{2}$  cup.
   1. Can Jana empty all three measuring cups into a 1 cup measuring cup? Explain.
   2. How much sugar does Jana have in total?
6. Joana needs $\frac{1}{6}$  cups of flour to make a dessert. Kent says that she should fill a $\frac{1}{2}$  cup measuring cup with flour first and then pour out enough to fill a $\frac{1}{3}$  cup measuring cup. He says $\frac{1}{6}$  cup of flour will be left over in the $\frac{1}{2}$  cup. Do you agree? Explain.
7. Greta must put $\frac{3}{2}$  of a teaspoon of baking soda in her cake batter. How many $\frac{1}{4}$  teaspoons is that?
8. Can the sum of two fractions equal the difference between the same two fractions? Explain.

Baking cookies for the family reunion

Betty is helping with the baking for the family reunion party next weekend. The following is their grandma’s famous chocolate chip and walnut cookie recipe.

Grandma’s recipe makes 50 cookies and Betty needs to make 150 cookies.

Help Betty figure out the fractions for the new recipe so they can prepare ingredients and make the mix at once.

When Betty collects the baking tools, they realize they are missing some of their measuring cups, like the $\frac{1}{2}$  cup. Betty only has the 1 cup and $\frac{1}{4}$  measuring cup to work with. Betty has the $\frac{1}{2}$  teaspoon as well.

Help her with number of cups and spoons of each ingredient to pour into her mixing bowl as well.

Use fraction strips, number lines or another method of your choice to show your work.

Reflection

As you read the following descriptions, select the one that best describes your current understanding of the learning in this activity. Press the corresponding button once you have made your choice.

Now, expand on your ideas by recording your thoughts using a voice recorder, speech-to-text, or writing tool.

When you review your notes on this learning activity later, reflect on whether you would select a different description based on your further review of the material in this learning activity.

Press ‘Discover More’ to extend your skills.

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