2. Fundamental Math Formulas & Rules Flashcards
What is the essential rule when Adding Expressions with Variables?
- In order to add 2 expressions that involve variables, it must be the case that the expressions are identical except for the numerical coefficient of the expression. (These are often called “like terms.”)
What is rule 1 of 3 when working with Addition and Subtraction Parity?
- If you add or subtract 2 numbers that are even, then the result will be even
What is rule 2 of 3 when working with Addition and Subtraction Parity?
- If you add or subtract 2 numbers that are odd, then the result will be even
What is rule 3 of 3 when working with Addition and Subtraction Parity?
- If you add or subtract 2 numbers that have a different parity (one of the numbers is even and the other number is odd), then the result will be odd
What is the formula for the Area of a Circle?
What is the formula for the Circumference of a Circle?
What is the essential rule when Converting from a Mixed Number to an Improper Fraction?
- Multiply the whole number by the denominator and add the numerator
What is the essential rule when Converting from an Improper Fraction to a Mixed Number?
- The numerator is the dividend, and the denominator is the divisor. Divide, and make the quotient into the whole number part of the mixed number. Make the remainder the numerator of the fraction, and keep the divisor as the denominator
What is the essential rule when Converting from Decimals to Fractions?
- Write any whole numbers by themselves. Next, write what is to the right of the decimal point (leaving off the decimal point) as the numerator (the top of the fraction). Determine which place the last digit of the decimal is in (tenths, hundredths, thousandths, etc.). The denominator (the bottom of the fraction) is the number that corresponds to that place. If the last digit was in the hundredths place, the denominator would be 100. If the last digit was in the tenths place, the denominator would be 10.
What is the essential rule when Converting from Fractions to Decimals?
- Perform long division by dividing the denominator (the number on the bottom) into the numerator (the number on the top). Keep using more 0’s after the decimal point (as needed) until the answer comes out even or the numbers begin repeating
What is the essential rule when Converting from Percents to Decimals?
- Take the percent amount, move the decimal point 2 places to the left, and remove the percent sign
What is rule 1 of 3 when Converting from Percents to Fractions?
- Use the percent amount as the numerator (the top number) of the fraction
What is rule 2 of 3 when Converting from Percents to Fractions?
- Always make the denominator (the bottom number) 100.
What is rule 3 of 3 when Converting from Percents to Fractions?
- Simplify the fraction if needed
What is the essential rule when dividing Expressions with Variables?
- For any nonzero number x and any 2 integers a and b, x to the a/x to the b = x to the (a - b). In other words, you subtract the exponents when you divide 2 like varables
What is the Divisibility Rule for 2?
- A number is divisible by exactly 2 when its last digit is divisible by 2; in other words, a number is divisible by exactly 2 when the last digit of the number is a 0, 2, 4, 6, or 8
What is the Divisibility Rule for 3?
- A number is divisible by exactly 3 when the sum of all the digits of the number is divisible by 3.
What is the Divisibility Rule for 4?
- A number is divisible by exactly 4 when the number created from its last 2 digits is divisible by 4
What is the Divisibility Rule for 5?
- A number is divisible by exactly 5 when its last digit is divisible by 5; in other words, a number is divisible by exactly 5 when the last digit of the number is a 0 or 5.
What is the Divisibility Rule for 8?
- A number is divisible by exactly 8 when the number created from its last 3 digits is divisible by 8