2 - Group 1 - Subtraction of Fractions Scripts
- 1. Subtraction of Fractions What’s a lot like addition like an addition, just remember that the denominators always must be the same. Let’s try three over five minus one over five. Let’s look at a cake, cut into five pieces. Three over five equals three pieces. Take away one fifth that is one piece. We are left two pieces. So, three fifth minus one fifth equals two fifth. But look what we really did. We just subtracted the numerators. Now let’s do one without pictures. Eleven over fourteen minus five over fourteen equals how much? Numerator will be eleven minus five, the denominator will be fourteen, which is equal to six. Therefore, the answer will be six over fourteen. We can reduce six over fourteen to three over seven. Now let’s try and subtract two fractions which have different denominator. Take three over four minus two over five. Here, we have to find the common the denominator which is the LCM. The LCM of four and five is twenty. Therefore, the denominator for both of fractions will be twenty. Change the first number three fourths, so that it has twenty as the denominator. And change the second number two fifths, so that is has twenty as the denominator. And the number will be fifteen over twenty minus eight over twenty equals seven over twenty. Let’s try one more. Two over five minus three over fifteen. The LCM will be fifteen. Two over five will become two mulitiplied by three over five multiplied by three, which is equal to three over fifteen. Thus, two over five minus three over fifteen will be six minus three over fifteen equals to three over fifteen. We can reduce three over fifteen to one over five