Chapter 7 Decimals, Real Numbers & Proportional Reasoning

Position Names

Expanded Form 25.3 = 2x x x = 1x x x x x = 1x x x x10 -3

Squares, Strips & Flats

Base Ten Blocks Activity 2c

Activity 1 &2

Negative Exponents = 1/ = 1/ = 1/ = 1/5 2

A negative exponent means I over. Usually a negative exponent means a fraction.

Converting Decimals to Fractions 17/40 = 17 ÷

Converting Decimals to Fractions.355 = 355 = 5 x 71 = x

Repeating Decimal.3333… …

Ordering Decimals To order positive decimals. Line up the decimal points and determine the first digit that is greater. (Add zeros at the end of the decimaqls to have the same number of decimal places.)

Irrational Numbers Non-terminating, non-repeating decimals … …… The square root of any non perfect square.

Homework Pg 431 # 1,2,3,5,6,7,8,10,31,32

Adding & Subtracting To Add or Subtract Decimals write the numbers in vertical style, lining up the decimal points and then add or subtract just as we add integers. BRING THE DECIMAL POINT STRAIGHT DOWN.

is 49. Our answer should be around

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Multiplying & Dividing Decimals.9 x.25 = 9/10 x 25/100 = 9 x 25 / 10 x 100 = 225 / 1000 = x x 1.8 Activity 5

2.5 x digit to the right of the decimal point 2 digits to the right of the decimal point 3 digits to the right of the decimal point

Think about what the answer should be. Where would you put the decimal point? Why?

digits to the right of the decimal point 1 digit to the right of the decimal point 3 digits to the right of the decimal point

471.2 X Think about what the answer should be. (2x471) Where would you put the decimal point? Why?

537.6 ÷ 2.56 = ÷ = x = 210

We don’t divide by a decimal, so we make the divisor a whole number. We multiplied the divisor by 100, so we have to multiply the dividend by 100 (move the decimal 2 places to the right.)

Homework Pg 441 # 1,2,4,10,32-35

Ratios & Proportions A comparison of 2 numbers by division. Ratio(nal) number Should express ratios in simplest form. Joe missed 12 free throws out of 45 attempts. Ratio of: Shots made to number attempted 33:45 Shots missed to number attempted 12:45 =4:15 Shots made to number missed 33:12 = 11:4

285 Boys & 228 Girls Ratio of: Boys to Girls Boys to students

One seventh of the students are nonswimmers. What is the ratio of nonswimmers to swimmers. Divide the students into 7 groups. 1 group will be non-swimmers.

Proportions A statement that says 2 ratios are equal. Then axd = cxb

28 x 21 = 49 x 12 = x

Marci liked to make mixed nuts by combining 6 cups of cashews with 2 cups of pecans. If she has 5 cups of pecans, how many cups of cashews does she need? If she has 20 cups of cashews, how many cups of pecans does she need?

The ratio of boys to girls in Mr. A’s class is 5 to 7 The ratio of boys to girls in Mr. B’s class is 2 to 5 What fraction of Mr. A’s class are boys? What fraction of Mr. B’s class are girls? There are 24 students in Mr. A’s class. How many are girls? If Mr. A’s class is bigger than Mr. B’s class, what would be a reasonable number of students in Mr. B’s class?

Similar Triangles

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Homework Pg 457 # 1 all, 2,3,4,5,637,38,39

Percents Percent from the Latin meaning per hundred. 25% = 25/100 Pg 463 Activity 11

3 Basic Problems Find x % of # =x 15% of 1750 % of x = # 15% of x is X% of a # is another # x% X 1750 =

% of # By Multiplying 15% of % X 1750 =.15 X 1750 =

% of # By Proportion 15% of 1750

% of # By Diagram:

% of x = # By equation 92% of x is X = 23 X = 23 /.92 X = 25

% of x = # By Proportion 92 X = 23 x 100 X = 2300 / 92 X = 25

X% of a # is another # x% of 35 is 28 By Equation X x 35 = 28 X = 28 / 35 X =.8 = 80%

X% of a # is another # x% of 35 is 28 By Proportion 35 x = 28 x 100 X = 2800 / 35 = 80%

45% of the students at a college are males. If the college has an enrollment of 22,500 students, how many are male? Use the 100 grid in your solution.

Homework Page 470 # 1,2,3,4,5,6all,7,9,10,37,38