Convert a measurement by multiplying by a conversion ratio arranged so the old unit cancels — the reasoning behind unit conversion, not a remembered rule.
Plot the pairs from a ratio table on the coordinate plane, see that equivalent ratios fall on a straight line through the origin, and read the unit rate at x = 1.
Find a unit rate when both quantities are fractions — half a mile in a quarter of an hour, three quarters of a liter in a third of a minute. Dividing by a fraction means multiplying by its reciprocal.
Decide whether two quantities are proportional, find the constant of proportionality in a table, graph, equation or description, write y = kx, and say what (0, 0) and (1, r) mean.