Evaluating expressions in two variables 2

The  exercise appears under the 6th grade (U.S.) Math Mission. This exercise continues to practice proficiency with replacing variables with numerical values, now with frequent fractions and decimals.

Types of Problems
There is one type of problem in this exercise:


 * 1) Find the value of the expression after substitution: This problem provides an algebraic expression with several variables and some values for those variables. The student is expected to find the numerical result when the values are substituted for the variables.Eeitv2-1.png

Strategies
Knowledge of decimals and fractions, along with the substitution property from algebra, are encouraged to ensure success on this exercise.
 * 1) The main difference between this and the level one problem is the more frequent decimals and fractions.
 * 2) A calculator may be against the spirit of the exercise, but can be used to increase accuracy. The numbers are reasonable so it can be more efficient to avoid calculators.

Real-life Applications

 * 1) Substitution is a proof justification in beginning algebraic proofs.
 * 2) The ability to evaluate expressions is essentially equivalent to evaluating formulas, which occur over all of science, economics and many other disciplines.