Question

The water level in a lake was monitored and was noted to have changed -2 1/3 inches in one year. The next year it was noted to have changed -1 5/6 inches. What was the total change in the water level over the two years?

Answer 1

The total change in water level over the past 2 years is
`\displaystyle -4 (1)/(6)`.

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Fractions

• Proper and Improper

Numbers

• Least Common Multiple (LCM)

Explanation:

Step 1: Define

Identify

Year 1 water change:
`\displaystyle -2 (1)/(3)`

Year 2 water change:
`\displaystyle -1 (5)/(6)`

Step 2: Find Total Water Change

1. [Set up] Add yearly water changes:
   `\displaystyle -2 (1)/(3) + -1 (5)/(6)`
2. [Fractions] Convert to improper:
   `\displaystyle (-7)/(3) - (11)/(6)`
3. [Fraction] Rewrite [LCM]:
   `\displaystyle (-14)/(6) - (11)/(6)`
4. [Order of Operations] Subtract:
   `\displaystyle (-25)/(6)`
5. [Fraction] Convert to proper:
   `\displaystyle -4 (1)/(6)`