Ratios with tape diagrams and number lines
Answers are for parents and teachers.
1
Girls to boys in a club are 4 : 5 and there are 36 children. How many girls and how many boys?
9 parts, one part is 4. Girls 16, boys 20. Check: 16 + 20 = 36.
2
Blue to white paint is 3 : 5 and there are 12 cans of blue. How many cans of white and how many cans in all?
3 parts are 12, so one part is 4. White: 5 × 4 = 20. In all: 12 + 20 = 32.
3
Make a ratio table for 4 : 7 with 4 columns. Which first number goes with the second number 21?
4 : 7, 8 : 14, 12 : 21, 16 : 28. The first number that goes with 21 is 12.
4
Juice A: 2 cups concentrate to 3 cups water. Juice B: 3 cups concentrate to 5 cups water. Which is stronger?
Make the water 15: A = 10 : 15 and B = 9 : 15. Juice A is stronger.
5
Rana says that 3 : 4 is the same as 5 : 6 because the second number is 1 more in each. Explain her mistake.
She compared differences. 3 : 4 × 2 = 6 : 8, which is not 5 : 6, so they are not equivalent.