How to tell my dad i did bad in algebra?

ok so the first quarter of algebra i got an 84 then it went down to a 76 as i started to get confused (i got the same score on my midterm) i tried asking my teacher but i still did not understand, we then had a big 3rd quarter test and i failed it miserably i would of kept my grade a 78 if i would of been able to correct it but she handed them back the day that the quarter ended i ended up getting a 65 and then our teacher left and we were given a male teacher. as we got into harder topics i asked him several questions about them but he would just give me one word answers, i did bad on the tests he assigned us and he gave a strict corrections policy that i wasnt told of so after i did all of the corrections he would only accept one of them my grade ended up being a 61 for the final quarter and i got a 50 percent on the final. my final grade was a 70 so i passed and the school is giving me study halls the next year to make sure i do better in math, all my other grades are B+s and some Cs and i dont know how to tell my dad i did bad in algebra, im in summer now and i do algebra an hour a day so i can learn what i didnt understand, im trying, i really am. is there any good way to tell my dad that without him grounding me ?