maths , chem bio and physics downfall

im giving my boards in mj 2025 and just got the results of my midterm. all my papers went so well excluding maths but when i got the results i did not exceed more than a B in sciences. i got a D in maths although i average an A star and A usually and in chem phy nd bio my exam went so well but in p6 i did not get more than 30 and p2 did not get more than 34 and p4 did not get more than 64. All my mistakes were idiotic. please any tips ANY TIPS!!!