Make them both improper fractions.
77/10 - 19/5
Give them common denominators (multiply the second fraction by 2)
77/10 - 38/10
Subtract
39/10 = 3 9/10
204 thousands equals to 204, 000 as the mathematical value and expression.
In expanded form
200, 000 + 4, 000 = 204, 000
In word form,
Two hundred and four thousand
That's not enough information to calculate your grade from.
-- You've told us the scores you have in things that go together
to make up (35 + 5 + 25) = 65% of your grade.
-- We don't know your scores in the things that make up the other
35% of your grade.