Putting Numbers in Perspective Chapter 2, Unit B Putting Numbers in Perspective

Essential Questions What situations do you see numbers that are really large or really small? What are some techniques we can use to put these numbers in perspective to gain meaning?

Scientific Notation Numbers between 1 to 10, multiplied by a power of 10 Change to Scientific Notation: move the decimal point to after the first non-zero digit The exponent is the number of times you moved left (+) or right(-) Change from Scientific Notation: Power of 10 tells you how many times to move the decimal right (+) or left (-) If decimal point creates any open places, fill with zeros

Practice: Change from Scientific Notation: 8x10^-2 5x10^3 9.6x10^4 2x10^-3 3.3x10^-5 7.66x10^-2 Change to Scientific Notation: 4327 904.35 0.0045 624.87 0.1357 98.180004

Approximations with Scientific Notation Multiplication/Division Multiply or divide the # Add (x) or subtract (/) the exponents Check to see if answer is in scientific notation Addition/Subtraction Change the numbers from scientific notation add or subtract Change the answer to scientific notation

Approximations with Scientific Notation (4x10^7) x (2x10^8) (3.2x10^5) x (2x10^4) (4x10^3) + (5x10^2) (9x10^13)/(3x10^10)

Order of Magnitude Estimates that only give a broad range of values Sounds like: “the population of the US is ‘on the order of 300 million’” which means it is nearer to 300 million than 200 million or 400 million When you would use it: Age in hours Number of breaths you take in a year Number of heartbeats in a lifetime How much we spend on ice cream in a year Amount of oil the US uses in a year

Your favorite… conversions! Tips to remember: To “cancel” a label it must be in the opposite location The final answer label must be in the numerator PRACTICE: Seconds in a day Hours in a year If you are going 50 mph, how many feet per second are you traveling

HOMEWORK: Calendar Adjustment D28: pp. 119-122 #15, 17, 19, 21, 23, 25, 27, 57-64