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From Counting to Addition 5
Figure 1-3
Items can be
counted by
twelves, but this is
not done much
nowadays.
digits are written side by side. The left-hand digit represents the number of tens,
and the right-hand digit represents the number of ones. Figure 1-4 shows how this
works for 35.
WHY ZERO IS USED IN COUNTING
If we have an exact count of tens and no ones are left over, we need to show that the
number is in “round tens” without any ones. To do this, we write a digit zero (0) in the
ones place, farthest to the right. This tells us that we have an exact number of tens
Figure 1-4
Writing numbers
bigger than 10.
When items are
left over, we put
the numeral representing
them in the
ones place.