# simple way to calculate without scientific calculator?

if r=0.00875 and n=180

formula is (1+r)^n

further (1 + 0.00875)^180 and the answer

is 4.797761, then how the 4.797761 get in simple calculator

• tony montana
1 month ago

well you need to do 1.00875 x 1.00875 x 1.00875 x 1.00875 x 1.00875….. so there are 18 1.00875s… its pretty time consuming, you’re better off using a scientific calculator.

If you don’t have one, you can always use one online:

http://my.hrw.com/math06_07/nsmedia/tools/Sci_Calc…

• friendlyhelp04
1 month ago

In the days before calculators, they used logarithms:

y = (1.00875)^180

log (y) = log [ (1.00875)^180 ]

log (y) = 180 log (1.00875)

using log tables, they’d find that log (1.00875) = 0.003784

Then multiply that by 180:

log (y) = 180 (0.003784)

log (y) = 0.681039

then using log tables, again, to find the inverse log:

10^(log (y) ) = 10^(0.681039)

y = 4.797761

You lose accuracy with log tables, because their precision is usually to 4 decimal places (more with interpolation, but you’d lose accuracy with that too).