This topic is in the 'Adding and Subtracting Fractions' section. Fractions represent dividing a whole into parts, and when those parts are equal, adding different fractions is almost the same as adding whole numbers. You'll see that with the tutorials focused on adding fractions with like denominators. The really cool thing is that when you've got fractions with unlike denominators, your strategy is to first convert all fractions to the same denominator (so that you're dividing whole numbers into the same number of parts), and then apply the lessons learned for fractions with like denominators. Make sure you focus with these tutorials- fraction skills are really key as you continue learning math.