Mathematics Ratio & Proportion Conceptual 12–14 yrs

Ratio Notation and Relationships

比率符号与关系

Description

Understand that a multiplicative relationship between two quantities can be expressed as a ratio; use ratio notation; simplify ratios

Mastery Evidence

✓ Explain why 'for every 2 red beads there are 5 blue beads' can be written as 2:5 or as 2/5 of the blue count
✓ Identify the multiplicative relationship in a table of values (e.g. y is always 3 times x)
✓ Connect the ratio a:b to the fraction a/b and to the linear function y = (a/b)x

Assessment Prompt

Can your child explain why a ratio like 3:4 is really the same as the fraction ¾ — and show how that relationship connects to a straight-line graph through the origin?