How do u write in a different way 300+70+5/10+8/100

well, 5/10 gives us the decimal of 5:10 or 0.5.

8/100 gives us the decimal of 8:100 or 0.08.

5/10 + 8/100 = 0.5 + 0.08, or 0.50 + 0.08, so they're both at the same decimal location, so 50 + 08 is 58, so 0.50 + 0.08 is 0.58.

300 + 70 = 370

370 + 0.5 + 0.8 is

370 + 0.58 = 370.58.