High school gpa help?

i was wondering how to calculate my highschool gpa. im only in 10th grade i take 2 honors classes math and science. in my school they weigh honors by multiplying your average by 1.04 im not sure how this affects my gpa. i have all 90's in all 5 academic classes and 2 electives and an 88 in phys. ed. If anyone can calculate my gpa, out of 4, i would greatly appreciate it! thanks!