Show the students the base strip, but have the percentage strip aligned to it but turned over so they can’t see the beads. Pose similar problems that the students can solve by aligning differently based strips with the 100-base strip. Mapping 18 out of 24 onto a base of 100 gives 75%. For example: “Tony got 18 out of his 24 shots. Pose the students a percentage problem that can be modelled with the percentage strips. Represent this on a double number line to show that finding a percentage is like mapping a proportion onto a base of 100. ![]() Represent this on a double number line.Īsk the students to work out what Sharelle’s shooting percentage was for the same game. Doubling 43 calculates the shooting percentage, as 43/50 is equivalent to 100 86. Who is the better shot?” Tell the students that percentages are used to compare fractions. Problem: “In a game of netball, Irene gets 43 out of her 50 shots in. Tell the students that the % sign comes from the “out of” symbol, /, and the two zeros from 100. They will often suggest sports (for example, shooting for goal), shopping (such as, discounts or GST), and, in country areas, calving or lambing percentages. Using Equipmentĭiscuss a situation where the students have encountered percentages in their daily life. Ratios and proportions can also be represented as decimals and percentages, e.g., 2/5 = 0.4 (equivalent to four-tenths) = 40% (equivalent to 40 hundredths). The fraction 2/5 can also be used as an operator, as in, “There are 45 beads. For example, a ratio of two reds to three blues (2:3) can be interpreted as the proportion two fifths (2/5) of the set or quantity being red. It’s important that the students understand the relationships between these three views of fractional (rational) numbers. ![]() The car used two-thirds of a tank-full in one trip. Do they meet the required adult : student ratio of 1:5?”įractional/Decimal Operators: The result of finding a fraction of a set or quantity, including other fractions, for example, “The petrol tank holds 41.7 litres. Ratio: How a set or quantity compares with another, for example, “A class has 6 adults to 28 students on a field trip. ![]() Proportion: How part of a set or quantity relates to the whole, for example, “Is 13 out of 20 a better result than 32 out of 50?” To become strong proportional thinkers, the students need to be able to find multiplicative relationships in a variety of situations involving fractions, decimals, ratios, and proportions.
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