Question

A dime has a diameter of about 18 millimeters. About how many millimeters long would a row of 34 dimes be?

Answer 1

It's hard to line them up exactly straight, with all of their centers
in a straight line.  It's much easier if you line them up on the floor
against a wall.

If you had 34 in a perfectly straight line, then the row would be

       (34) times (18 millimeters) =  612 millimeters long .

Answer 2

The row would be (34*18) 612 millimeters long