3.6 Solving Decimal Equations

Objective: Find exact and approximate solutions of equations that contain decimals.

How it feels to teach class…

If the number you are rounding is followed by

a 5,6,7,8, or 9 then you round the number up. ex: 41.8 would round up to 42

If the number you are rounding is followed by a 0,1,2,3, or 4 then the number stays the same. Ex: 41.3 would round to 41

Rules for Rounding

Decimal Places

Round 7.8199 to the nearest tenth.

Round 1.0621 to the nearest hundredth

Round 3.8792 to the nearest thousandth

Practice

Always Remember!!!

Round the Final Answer to the nearest

hundredth. -38x – 39 = 118

24x + 43 = 66

22x – 39x = 19

Solve the equation and round to the nearest

tenth. 3.5x – 37.9 = 0.2x 2.4x – 0.9 = 12.4

Solve the equation and round to the nearest

tenth. 14.7 + 2.3x = 4.06 3.25n – 4.71 =

0.52n

Three people want to share equally in the

cost of a pizza. The pizza costs $12.89. What is each person’s share?

Round for a practical answer.

Four people are sharing the cost of a monthly

phone bill of $58.25. What is each person’s share of the bill?

When you say “Percent” you are really saying

“per 100”

To convert a percent to a decimal, you move the decimal point two places to the left.

To convert decimal to a percent, you move the decimal point two places to the right.

Percents