let 'count = 1.2 * 100' error

I am trying to test some multiply function under bash shell, as you can see from the following

$ let 'count = 1.2 * 100'
bash: let: count = 1.2 * 100: syntax error in expression (error token is ".2 * 100")

does not work, seems bash shell does not like ".2"

$ let 'count = 1 * 100'

without .2, accepted,

So my question is, how can i let bash shell do the 1.2 * 100?

Thanks!

Just about every shell I am familar with does not do floating point math. Integer only.

you can echo your formula into bc for the same result.

echo "1.2*100"|bc

returns
120

ha, cool, it works and thanks a lot!