( 78 ) 
fo many tens of millions of units, and fo 
on: thus you perceive all numeration, be 
the fum ever fo great, is no more than a 
repetition of the denominations of the three 
firil figures. 
Thefe obfervations may appear trivial. 
Euclid's Geometry is built on felf-evident 
propofitions, which, to a learner, always feem 
trifling. It is impoflible to begin the ftudy 
of any Science too near its fource. 
We now proceed to the firft and mod 
fimple operation of Arithmetic called Addi- 
tion i for example 
To 25, the quarter of a hundred 
Add 75, three quarters of a hundred 
Sum 100 
I reafon thus, 5 and 5 make 10; but I 
cannot put down ten in the unite's place, 
therefore I carry in my mind, this ten to 
the 7, which {lands in the ten's place ; thus 
the 7 becomes an 8, and this 8 added to the 
2, makes ten tens. Now ten tens make one 
hundred; therefore I write a cypher in the 
ten's place and a one in that of hundreds : 
for, as I have but ten figures to work with, 
and as each of thefe exprefles units only, I 
can put down, after each addition, no more 
a than 
