Losing silly marks in maths

In my maths papers, I find that I'm consistently losing marks for stupid mistakes even if I know what's going on in the question. The grade boundaries keep creeping up for maths too so I'm concerned that I could drop a grade by getting stuff wrong that I could otherwise do. Anyone got any tips to reduce this? I check through my answers at the end of papers but I don't alway get enough time to redo all of them and I tend to not catch my errors