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Middle School HowTo
Math Middle School Review
Question | Answer |
---|---|
How do you add/subtract fractions? | Make Improper - Find Common Denominator - Add/subtract top numbers - Simplify |
How do you multiply fractions? | Make Improper - Multiply Across - Simplify |
How do you divide fractions? | Make Improper - Change division to multiplication and flip 2nd fraction - multiply straight across - Simplify |
How do you multiply decimals? | Multiply like normal - count decimal spots in each number - move decimal over number left the amount of the sum |
How do you add/subtract decimals? | Line up decimal places - add zeroes in empty spots - add/subtract like normal |
How do you change % into a decimal? | Divide by 100 or move decimal 2 spots left |
How do you change decimal into %? | Multiply by 100 or move decimal 2 spots right |
How do you change % into a fraction? | Put the % over 100 - move decimal of top and bottom if needed - simplify |
How do you change a fraction into a decimal? | Long division - Top divided by bottom |
How do you find the percentage of change? | Find the change by subtraction - divide by the original amount - convert into % form |
What is the percent proportion? | Part/Base = %/100 |
How do you solve proportions? | Set up 2 fractions (make unknown on top) - multiply both sides by bot term - include units |
How do you find percent given part and base? | Divide part by base - change into % form |
How do you find part given percent and base? | Change % to decimal - multiply by base |
How do you find base given part and percent? | Divide part by percent and multiply by 100 |
How do you calculate taxes/discounts? | Change % to decimal - multiply by cost - add/subtract to find total cost |
How do you write a number in scientific notation? | Move decimal between 1st two digits - count spots moved and that is exponent of the 10 |
How do you change a number from scientific notation? | Move decimal amount of spots in the 10 exponent - add zeroes in blank spots |
How do you find mean (average) of a data set? | Add numbers and divide by how many there are |
How do you find mode of a data set? | Whichever number appears most often |
How do you find range of a data set? | Find difference between top and bottom terms |
How do you find a unit rate? | Write fraction with units - set it equal to fraction over 1 - divide to find top value |
How do you find simple interest? | I = Prt - P-money start with, r-rate as decimal, t-time in years |
How do you find the probability of 1 event? | Fraction where you put outcomes of success over total possible outcomes |
How do you find the probability of multiple events? | Multiply probability fractions of each individual event occuring |
HOw do you multiply/divide negatives? | Multiply/divide like normal - add sign where same signs make positive / different negative |
How do you find area of a circle? | Area = pi x radius squared = 3.14 x r x r |
How do you find area of a rectangle? | Area = length x width = l x w |
How do you find area of a triangle? | Area = 1/2 x base x height = 1/2 x b x h remember base and height are perpendicular |
How do you find perimeter of a shape? | Add the lengths of the sides together |
How do you find distance around a circle (circumference)? | C = pi x diameter = pi x 2 x radius |
How do you find volume of a prism? | V = area of base x depth = A x d |
How do you find volume of a cone or pyramid? | V = 1/3 x area of base x depth = 1/3 x A x d |
How do you find Surface area of a shape? | Add areas of each face together |