Solve problems involving ratios. Number Framework Stage 8
Discuss a situation where the students have encountered
percentages in their daily life. They will often suggest sports
(for example, shooting for goal), shopping (such as discounts or
GST), and, in country areas, calving or lambing percentages.
Tell the students that the % sign comes from the “out of”
symbol, /, and the two zeros from 100. It means, “out of 100”.
Problem: “In a game of netball, Irene gets in 43 out of her 50
shots. Sharelle takes 20 shots and gets in 17. Who is the better
shot?” Tell the students that percentages are used to compare
fractions. In Irene’s case, the fraction is 43/50 . Doubling 43
calculates the shooting percentage because 43/50 is equivalent
to 86/100 (86 out of 100). Represent this on a double number
line. Ask the students to work out what Sharelle’s shooting
percentage was for the same game. Represent this on a double
number line to show that fi nding a percentage is like mapping a
proportion onto a base of 100. Pose