When trying to figure up sales tax on a problem how would one write it out I have searched the site some say 1.05 some say 0.05 and something about moving a decimal over 2 spaces to the left. Im not getting it Like the problem is 3 shirts is 9.99 ea we know this is $29.97 then it says add 5% sales tax ?

All of the suggestions are correct and will give you the same answer.

Note that 5% = 5/100 = 0.05

Here's my way.

$29.97 times 0.05 = $1.498 = $1.50.

The sales tax is $1.50

29.97 + 1.50 = $31.47