How the Intel give number to their 8085 and 8086 microprocessor?

Intel named the 8085 after the 8080. The 5 means it runs on a single +5V power supply, as opposed to the 8080 which needed +5V, -5V, and +12V. The predecessors of the 8085 were the 8080, 8008, 4040, and 4004.

Intel named the 8086/8088 after the 8085. It was considered the logical continuation of the 8085 family, but as a true 16-bit processor. The 8086 is a 16-bit computer running on a 16-bit bus. The 8088 is the same 16-bit computer, but it runs on an 8-bit bus, and it was the heart of the first IBM PC.