The print version allows teachers to use the problem with their students without giving the students access to the archived answers.
Teachers can use the link to the archived problem to get ideas of student thinking.
The Galactic Exchange problem requires students to determine coin values and product prices from an alien vending machine. Since the American money system, a decimal system, is a familiar experience, the complication of a non-decimal system becomes clear as soon as one tries to understand a system where 12 pennies make a shilling and 20 shillings make a pound, but 2 shillings 6 pence make half a crown. Exercises in this field can provide pre-algebra practice in the area of variable substitutions. Please email us. Algebra - relate and compare different forms of representation for a relationship.