7.EE.3: Strategic Problem Solving with Rational Numbers: Operations, Conversions, and Estimations

Grade: 7th Grade

Domain: EE: Expressions and Equations

Standard Description

Solve multi-step real-life and mathematical problems posed with positive and negative rational numbers in any form (whole numbers, fractions, and decimals), using tools strategically. Apply properties of operations to calculate with numbers in any form; convert between forms as appropriate; and assess the reasonableness of answers using mental computation and estimation strategies. For example: If a woman making $25 an hour gets a 10% raise, she will make an additional 1/10 of her salary an hour, or $2.50, for a new salary of $27.50. If you want to place a towel bar 9 3/4 inches long in the center of a door that is 27 1/2 inches wide, you will need to place the bar about 9 inches from each edge; this estimate can be used as a check on the exact computation.

Domain Description

Strategies for operations properties can be used to add, subtract, factor, and expand linear expressions with rational coefficients. By rewriting an expression in different contexts, we can gain better insight into the problem and the relationships between the quantities. Using the formula a + 0.05a = 1.05a, we understand that increasing by 5% is the identical to multiplying by 1.05.

Complex mathematics and real-life problems involving positive and negative rational numbers can be solved using numbers in any form with the appropriate tools. For proper calculations, convert various forms; assess the validity of results by mental computing and estimating. Example: If a woman gets a 10% raise on her $25 hourly wage, that translates to an additional $2.50, raising her hourly wage to $27.50.

Word problems leading to px + q = r and p(x + q) = r, where p, q, and r are specific rational numbers can be solved with fluency; you can also compare the algebraic solution to an arithmetic one. For example, to calculate the width of a rectangle with a perimeter of 54 cm and length of 6 cm.

Solutions can be found and