# In-ven-te-gers

Integers—all the counting numbers (1, 2, 3…), their opposites (^{–}1, ^{–}2, ^{–}3…), and zero (0)—can be plotted on a number line. Your child can make an “invention” time line to show integers that “span” thousands of years!

## What You Need:

- Several sheets of paper
- Tape
- Ruler, yardstick, or meter stick
- Pencil with eraser
- 12 index cards
- Colored pencils or markers

## What You and Your Child Will Do:

- You and your child will do research on inventors and inventions. Find six inventions of inventors who lived BCE (Before the Common Era) and six inventions whose inventors live(d) CE (in the Common Era). (1892 CE corresponds to 1892 AD; 456 BCE corresponds to 456 BC.) On an index card, record the information for each inventor and invention, along with the date of the invention.

Tip: Many electronic and print resources are available on the subject of inventors and inventions, such as David Macaulay's books,**The Way Things Work**©1988 and**The New Way Things Work**©2003, Boston: Houghton Mifflin Company. - To make a time line, tape paper end to end until there is enough room to draw a line long enough to accommodate the 12 index cards. Hold the ruler to help your child draw a long line from one end of the first paper to the far end of the last.
- Help the child decide where to place the point at which the two eras meet. This point may be indicated by “0”. Have your child arrange the index cards along the line, according to the years of the inventions: the BCE inventions to the left of the 0 and the CE inventions to the right of the 0. (Remember, the earlier the invention, the farther to the left it will be.)
- Have the child move the cards below the number line. Then the child can record the invention and the year of its invention using integers (i.e., 345 BCE would be
^{–}345, 1054 CE would be 1,054) on the number line.