However, students who write carelessly may mistake a lower case L for a one, and an S for a 5. One student in my class selected "B" and "T" for "Big" and "Tiny," thus avoiding the issue altogether.
Sum of Two Fractions: This system can be solved by clearing the equations of fractions and then solving, or by carrying the fraction through the problem.
Strictly speaking, the age problem also has three unkowns: Bob's age, Bart's age, and Bart's age two years from now.
Students will hopefully see quickly that Bart's age in two years is 2 more than it is now.
In order to show an understanding of the problem you of course need to read the problem carefully.
Sounds simple enough, but some people jump the gun and try to start solving the problem before they have read the whole problem.Do whichever seems more suitable for your class, or show both ways of solving.Keep in mind that clearing the fractions causes it to no longer be a simple substitution problem.This is the simplest kind of system of equations to solve.In fact, many students will solve these kinds of problems without even thinking of it as a system of equations.The word problems in this section all involve setting up a system of linear equations to help solve the problem.Basically, we are combining the concepts from Tutorial 16: Formulas and Applications, Tutorial 49: Solving Systems of Linear Equations in Two Variables and Tutorial 50: Solving Systems of Linear Equations in Three Variables all rolled up into one tutorial.Bob and Bart's names were specifically chosen to force students to recognize that B can't be used as a variable for both, and another choice must be made for one of the boys.The shortest side of a triangle has length 16 inches. For this lesson, we require students to use two variables (or more), making these problems a nice transition from single-variable problems to systems problems.Each of these systems is easily solved using substitution.