10 
ON THE VALUE OF ANNUITIES. 
present value of an annuity of £50 for 6 years, at 3^ per cent simple 
interest, 
1 
v 1 
== .966184 
1 + i 
1.035 
1 
1 
= .934579 
1 + 2 i 
1.07 
1 
1 
= .904977 
1+3* 
1.105 
1 
1 
= .877193 
1 + 4* 
1.14 
1 
1 
= .851064 
1 + 5 i 
1.175 
1 
1 
= .826446 
1 + 6 i 
1.21 
5.360443 
50 
5 360443 present value of an annuity of £l 
\ for 6 years 
268.02215 = ditto 
£50 
To mathematicians, the tables just mentioned will he found of great 
use, as they contain the factors, squares, cubes, square roots, cube 
roots, and reciprocals of all numbers from 1 to 10,000, with other tables, 
and an extensive collection of formulae relating to mathematics and 
natural philosophy. 
i. e. as 
since 1 
amount 
and prc 
n th year 
Rule. 
same poi 
principal 
Examj 
compound 
COMPOUND INTEREST. 
19. When the interest of money, instead of being received as it 
becomes due, is added to the principal, increasing the sum each year on 
which interest is receivable, then money is said to be put out at Com 
pound Interest. 
If the interest of £100 at ¿£5 per cent, instead of being taken up at 
the end of the first year when it becomes due, he added to the principal, 
a new principal of ¿£103 is created, which with its interest amounts at 
the end of the second year to ¿£110 5, this again forms a new prin 
cipal amounting with interest to ¿£115 15 3 at the end of the third 
year, and so on for any longer period. 
Make s the amount 
p — the principal 
n — the number of years 
i ~ the interest of ¿£l for one year; 
then 1 + i — the amount of ¿£l at the end of the first year, and the 
amount of any other sum in one year will be in the same proportion, 
In this 
termed com 
(Arithmetic 
L °g(l 
lo SP 
Rules for 
the different