VIDEO #1 Intro to Ratios
https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratios-intro/v/ratios-intro
VIDEO #2 Basic Ratios
https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratios-intro/v/ratio-example-problems
VIDEO #3 Part : Whole Ratios
https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratio-word-problems/v/ratios-as-fractions
VIDEO #4 Part : Whole Ratios Word Problem
https://www.khanacademy.org/math/pre-algebra/pre-algebra-ratios-rates/pre-algebra-ratio-word-problems/v/ratio-word-problem-exercise-example-1