02.28.2018: One Chapter of Math

Today's soundtrack is Myrkur: Mareridt.

I'm now on chapter 10 of Basic Math & Pre-Algebra For Dummies, "Parting Ways: Fractions and the Big Four Operations," which deals with how to add, subtract, multiply, and divide fractions.

To multiply fractions, just multiply the numerators by each other, and the denominators by each other, and hey presto! -- the answer. For example, 1/2 x 3/4 = 3/8.

If the numerator of one fraction and the denominator of the other fraction are the same, cancel them out by making them both "1."

If If the numerator of one fraction and the denominator of the other fraction are both divisible by the same number, then divide them by that number before calculating.

To divide a fraction by another fraction, just multiply the first fraction by the reciprocal of the second.

To add two fractions with the same denominator, simply add the numerators together. Easy as.

To add two fractions together with different denominators, (my method is to multiply the two numerators by the other, then multiply the two denominators by each other, then add the two together, then reduce) we cross-multiply the two fractions and add the results together to get the numerator of the answer, then multiply the two original denominators to get the answer's denominator. Repeat as needed if there are more fractions to add.

To subtract fractions with the same denominator, subtract one numerator from the other, and keep the denominator the same. Done.

To subtract fractions with different denominators, (my method is the same as mentioned above in my notes about addition), cross-multiply the two fractions and subtract the second number from the first to get the numerator of the answer, then multiply the two denominators to get the denominator.

To perform any of the big four operations on mixed numbers, they must first be converted to improper fractions, then calculated as laid out above.