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A time line is a useful way to represent important dates and events throughout history. It's common to divide a historical time line into events that
occurred either BC (to the left of zero) or AD (to the right of zero). The year you're living in right now takes place in AD.
BC AD
0
When performing mathematical operations involving dates, we can think of a historical time line as a number line. On the number line, the years
increase from left to right. If zero represents the origin, the years to the right of zero are considered positive numbers and the years to the left of zero
are considered negative numbers. Using this analogy, here are some events that might appear on a historical number line:
Event
Historical Time Line Number Line
The first ancient games take place in Olympia, Greece, 776 BC
-776
Construction begins on the Great Wall of China
221 BC
-221
World War I begins in central Europe.
AD 1914
1,914 (or 1914)
Use these ideas about time lines and number lines to answer the questions that follow.
Part A
The year in which the US Civil War ended was 25 percent later than the year Christopher Columbus set sail from Spain. If c represents the year
Columbus set sail, we can write the year the Civil War ended as c +0.25c. Rewrite this expression as a single term
B.
