1. Algebra 1 Section 3.6 Find approximate solutions to equations using rounding techniques Three people want to share equally in the cost of a pizza. The pizza costs $12.89. Find each person’s share. Total cost = (number of people) x (cost per person) verbal model $12.89 = 3x algebraic equation x = 4.2966 solution $4.30 per person answer When calculating money values, round to the nearest $.01 (hundredth) http://www.khanacademy.org/math/arithmetic/decimals/v/rounding-decimals

2. Solve and round to the indicated value. 47x – 36 = 18 47x = 54 x = 54/47 x = 1.148936 Nearest hundredth. 1.15 Nearest tenth. 1.1 Nearest unit. 1

3. Some quantities such as money values are always rounded to the nearest $.01, other values are rounded according to the number of significant figures involved in the computation. What are significant figures? http://www.khanacademy.org/math/algebra/exponents radicals/v/significant-figures How many significant figures? 13.5 cm 3 120 2.000 056 2 40. 2 1406 4

4. There are rules for using significant figures (digits) when multiplying. Rule for multiplying and dividing sig figs: The product or quotient can have no more sig figs that the factor with the least amount of sig figs. (Significant figures are used when measurements are used in the calculation.) Perform the operation using the significant figures rule 1.2 cm x 1.6 cm 125 ft 2 3.5 ft http://www.khanacademy.org/math/algebra/exponents-radicals/v/multiplying-and- dividing-with-significant-figures 1.9 cm 2 36 ft

5. Rule for significant figures when adding or subtracting http://www.khanacademy.org/math/algebra/exponent s-radicals/v/addition-and-subtraction-with-significant- figures Simplify: 12.5 cm + 1.452 cm 13.952 cm -> 14.0 cm 4.75 m – 1.2 m 3.55 m -> 3.6 m Rule for significant figures for adding and subtracting: When adding or subtracting, your answer can be only as precise as the least precise measurement.

6. You are shopping for ear rings. The sales tax rate is 5%. You have a total of $18.37 to spend. What is your price limit for the earrings? x +.05x = $18.37 1.05x = $18.37 x = $17.4952381 Normally, you would round up to $17.50, however, if you only have $18.37, you don’t have the extra money to round up, so your price limit is $17.49

7. Assignment Complete worksheet