Multiplying and dividing fractions is often easier than adding them. To multiply, multiply the numerators and multiply the denominators. To divide, flip the second fraction and multiply. For example, and . When you are done, simplify the answer if the top and bottom share a factor. Before this lesson: You should know how to simplify…
Adding and subtracting fractions is easy when the denominators match: add or subtract the numerators and keep the denominator. If the denominators are different, first rewrite the fractions with a common denominator. For example, . Then simplify the answer if you can. Before this lesson: You should know how to write equivalent fractions and how…
The least common multiple (LCM) of two numbers is the smallest number that both of them divide into with no remainder. To find it, list the multiples of each number until you find one they share, or use prime factorization. For example, the LCM of 4 and 6 is 12. Before this lesson: You should…
The greatest common factor (GCF) of two numbers is the largest number that divides both of them with no remainder. To find it, list the factors of each number, or use prime factorization. Then pick the biggest factor they share. For example, the GCF of 12 and 18 is 6. Before this lesson: You should…
Prime factorization means writing a number as a product of prime numbers. A prime number has exactly two factors, 1 and itself, like 2, 3, 5 and 7. To find the prime factorization, split the number into factors until every factor is prime. For example, . Before this lesson: You should know your multiplication facts…
Multiplying and dividing integers uses two sign rules. If the two numbers have the same sign, the answer is positive. If they have different signs, the answer is negative. So and . Multiply or divide the numbers as usual, then use the sign rule. Before this lesson: You should know negative numbers and adding and…
Adding and subtracting integers follows three rules. If the signs are the same, add the absolute values and keep the sign. If the signs are different, subtract the smaller absolute value from the larger one and keep the sign of the larger. To subtract, add the opposite: . Before this lesson: You should know how…
The coordinate plane is a grid made by two number lines that cross at 0. The flat one is the x-axis, and the up-and-down one is the y-axis. Every point has an ordered pair . To plot (3, −2), start at 0, move 3 right, then move 2 down. Before this lesson: You should know…
Nested fractions, also called complex fractions, have a fraction in the top, the bottom or both. To simplify one, remember that the main fraction bar means divide. Simplify the top and the bottom, then divide the top by the bottom. For example, . Before this lesson: You should know how to add and subtract fractions…
The circumference of a circle is the distance around it, C = 2πr or C = πd. The area is the space inside, A = πr². Pi is about 3.14.
