5,3=

Do you mean one of these?

• 5,3 as a decimal (European notation): 5,3 = 5.3
• The fraction 5/3: 5/3 = 1.666… (1 2/3)
• The ordered pair (5,3) as a vector: magnitude √34 ≈ 5.83, slope 3/5 = 0.6

Please tell me which interpretation you want, or provide more context.