We can also use numbers to index into RAM as follows:
[750] ; offset
[rbp] ; base register
[rcx + rsi*4] ; base + index * scale
[rbp + rdx] ; scale is 1
[rbx - 8] ; offset is -8
[rax + rdi*8 + 500] ; all four components
[rbx + counter] ; offset is the address of the variable 'counter'
Example:
mov rbx, [rbp] ; rbx = RAM[rbp]