Name______________________ MATH 7 everything notes Decimals Add zeros to the end of a # as necessary Mental Math 10% = .10 = .1 1% = .01 to mult by 10% move decimal left once to mult by 1% move decimal left twice Ex. 12% of 30 10% = 3 so 1% = .3 so 2% = .6 so 12% = 10% + 2% = 3 + .6 = 3.6 Name______________________ MATH 7 everything notes ROUNDING If 5 or more round before up 1 Ex. Round 1.596 to the hundredths place Underline the 9 in the hundredths place Look at the right spot, 6, so round 9 up to 10 or the 59 up to 60 Answer: 1.60 (0 needs to be in hundredths spot) COMBINING INTEGERS SIGNS ANSWER Same Add and Keep the Sign Subtract and take the Sign of the Bigger Absolute Value Different Adding and Subtracting Integers Positive right or + for a chip Negative left or – for a chip !!!!!Change subtraction to adding the opposite!!!!! 3 – 7 = 3 + -7 Ask Yourself “Are there more negative or more positives?” “How many more?” Chip example: - 5 – (-14) or - 5 + 14 Negative = Remove For real life word problems Say 5 negatives and 14 positives, how many more positives? 9 positives so +9 (there are 5 zero pairs that cross off) Name______________________ MATH 7 everything notes FRACTIONS MIXED TO IMPROPER: Mult then add, keep denom, recopy any neg signs ADDING (or subtracting) FRACTIONS: Must have common denominator, find LCD Multiply by Special One MULTIPLYING OR DIVIDING INTEGERS Factors: if there is one neg it’s neg Ex. + = LCD: SIGNS ANSWER Same Positive Different Negative i Multipling Fractions: block[3].htm 1. Change to improper, write down + or - sign for answer 2. Numerator times numerator, denom times denom 3. Reduceblock[4].htm during problem, numerator ÷ denominator block[4].htm Dividing Fractions: 1. Change to improper, write down + or – sign for answer 2. STAY, CHANGE to mult, FLIP (2nd fraction (reciprocal)) 3. Mult across, reduce up and down Name______________________ 0 MATH 7 everything notes 0 00 Comparing and Ordering #’s Must have like units, all fractions with common denominator, get decimals by doing division, add zeros so everything has same # of digits Example: Conversions fraction, decimal , % 2 ½ = 2.5 = 250% Frac decimal just divide Decimalfrac Say it using correct place value, then reduce Constant of Proportionality = k or y = kx graph of a line through origin (0,0) K Something is proportional if you divide and get the same # every time Example to right: (0,0) (1,9) (2,18) y/x = 9/1 = 18/2 so k = 9 Name______________________ MATH 7 everything notes Ratio and Proportion Q: Find the number of feet in 96 inches Cross multiply Simplify divide Make sure to LABEL & match up units. Write conversions as a ratio. Cross multiply. Divide by coefficient. Sometimes you may have to do more than one proportion to finish a problem. ie. seconds in a year…. SCALE FACTOR # you multiply by Percent Proportion Find it by doing new ÷ old Markup, % increases, Tax, Tip - % added on Markdown, % decreases, Discount - % taken off Example: Find the % increase if I used to weigh 110 and now I weigh 135. % / 100 = amount increase / original total What is your total after taxes (8%) on a $20 Bill? % after tax / 100 = amount after tax / original $ Name______________________ MATH 7 everything notes SIMPLIFYING EXPRESSIONS Change subtraction to adding the opposite Distribution Keep signs in mind when you distribute, copy the other stuff down Organize like terms Use the # line or chips if necessary 3x When you have more than one, do whichever comes 1st If there are two multiplications than left first If division is before multiplication do division 1st A or S whichever comes 1st Name______________________ MATH 7 everything notes Exponent Rules 8th Writing Equations of Lines: Given 2 points is the hardest one. You could also be given the slope and y intercept already. You could be given 1 point and the slope, so you solve for b. Y = -3.5x + 17.5 You can also graph what you are given and write equation from looking at the slope (rise over run) and the y intercept Name______________________ MATH 7 everything notes 8th DEFINITION OF A FUNCTION: Every x has only one y X (input) Y(output) VERTICAL LINE TEST: If you draw vertical lines over your graph or plotted points and it only touches goes through 1 point it passes. This graph is a function Not a function. One element of the domain Matches with more than one element of the range. FROM A TABLE OR LIST: FUNCTION: (0,1) (1,1) (2,1) no repeated x’s NOT A FUNCTION: (1,-3), (2,4) , (1,5) has repeated x’s Take your information and change it to a mapping diagram, a list of points or a graph as you wish Solving Equations Name______________________ MATH 7 everything notes 5(x+3) – 2x = 11 – x 5x + 15 – 2x = 11 – x 3x + 15 = 11 – x +1x +x 4x + 15 = 11 - 15 - 15 4x =-4 4 4 x = -1 1. ( ) Distribute 2. Same Side Combining (try keeping x positive) 3. Opposite Sides Opposite 4. Get rid of + or 5. Get rid of Mult or Divide 6. Check Rewrite, Substitute, Verify w/ Pemdas **A check is a good way to do a multiple choice question.** < less than ≤ less than or = to, cannot exceed, at most, maximum > greater than, more than ≥ greater than or = to, at least, minimum ** REMEMBER – Write the x on the left BEFORE you graph. FLIP INEQ. when you Mult. or Divide by a NEGATIVE!! INEQUALITIES Name______________________ MATH 7 everything notes GCF – finding the greatest common factor which will divide into all terms evenly, reverse distributive property Factor Trees help. Factor 18x – 21y Both trees have one 3, so gcf = 3 answer: 3(6x-7y) __________________________________________ DISTRIBUTING Example: 18x2 + 24 x = 6x(3x + 4) FACTORING More Advanced 2 GCF is 4xy 4xy( 9x + 4)= 36x2y + 16xy PROBABILITY & STATISTICS TREE DIAGRAMS: BRANCH OUT FOR EACH NEW CATEGORY OR TRIAL P(E) = Prob of an Event Toss a coin 3 times 52 cards, JQK face 13 in each suit, Heart & Diamonds Red, Spades & Clubs Black Name______________________ MATH 7 everything notes Counting Principle and Permutations: Make lines for number of categories and put in the # of choices. Permutations: How many ways can Horses come in 1st, 2nd and 3rd in a race of 8 horses 8 7 6 1st 2nd 3rd Counting Principle: How many 5 digit combinations can you make, repeats allowed 10 1st 10 10 10 10 2nd 3rd 4th 5th Read carefully! Read Carefully! Repeats oror Not Repeats Not etc. … ex. P(Red Card and flip Head) = STATISTICS e Name______________________ MATH 7 everything notes BOX PLOT: Put numbers in order, cut them half, cut each half in half, plot on # line List: 15 16 17 18 | 20 21 21 21 | 22 23 24 25 | 25 29 29 29 min Q1 med Q3 max distance around Space inside Remember: Cherry is Delicious Apple ’s aRe 2 Area and Perimeter Review Base and height always make right angles Name______________________ MATH 7 everything notes Triangles Triangle Inequality 5 + 3 > 7 yes so makes triangle Short side + short side > long side 8th grade Name______________________ MATH 7 everything notes Angle Info! Name______________________ MATH 7 everything notes MATH 7 everything notes Name______________________ Volume of a Prism A prism is a polyhedron with two parallel, congruent faces called bases that are polygons. STEP 1: Name the shape STEP 2: COPY FORMULA ONTO PAPER STEP 3: Recognize the b and h STEP 4: Substitution Volume units are in units cubed (in3 , ft3 , cm3 , m3 , et cetera). STEP 5: Evaluate (use calculator) The volume V of a prism is the (AREA OF BASE) B times the height h . OR Volume Pyramid = (Area of Base Shape x Height) / 3 V =(A x H ) / 3 Area of Triangle Base = .5 b h = .5(8)(14)= 56 V = (56 x 17) / 3 = 317. Name______________________ MATH 7 everything notes Transformations
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