How do you calculate percentage grades?

Three exams are worth 90% of the final grade and the other 10% comes from journals. How do I calculate my final grade?How do you calculate percentage grades?
take the number of points the test was

subtract the number you got wrong

multiply that number by four

thats ur percentage!!!How do you calculate percentage grades?
take your percentage on your test (say 80%) and multiply it by what their worth (90%)

80*.9 (write as .9 because it is worth .9 of your grade) = 72

Now do the same thing for your journals (say 70%)
70*.1 = 7

Now add the two together and you have your grade