Three teams are racing through the Chilean countryside. As you're reporting live on their progress, you need to add and subtract fractions with unlike denominators quickly. Can you do that? Grab your pencil, and let's get started!

A fraction shows part of a whole. The number on top is called the numerator, and the number on the bottom is the denominator. When the denominators are different, like in 7/9 + 1/6, the pieces are not the same size. These are called fractions with unlike denominators. To solve them, you first need to find a common denominator. That means a number both 9 and 6 can turn into. That number is 18. Next, change each fraction into an equivalent fraction with 18 as the denominator. Since 9 ÷ 2 = 18, multiply 7 by 2 to get 14/18. For the second fraction, multiply both numerator and denominator by 3 to get 3/18. Now just add the numerators: 14 + 3 = 17. That gives you 17/18. Look, the teams are coming around the bend. Ready? Three, two, one... go!