We now come to the method of teaching the combinations in Addition and
Subtraction.
We can count books, tables, and houses and say that we have counted so
many _things_ but we do not _add_ books, tables, and houses. We _add_
books and books, tables and tables, houses and houses.
We count by _ones_. When we add three beads and two beads we are
counting by ones, for it means that we are adding three ones of beads
and two ones of beads, making five beads in all.
From =1= to =9= we use only one figure to tell how many we mean. When we
wish to say in writing that we have ten of anything we write a =0= after
the =1= and have =10=, ten.