10^10000 is a large number, but it is surpassed only by the 47,852th Fibonacci number -- a small number of iterations for a computer. I often suppose as a rule

10^10000 is a large number, but it is surpassed only by the 47,852th Fibonacci number -- a small number of iterations for a computer. I often suppose as a rule of thumb that a C program can perform ~10 million for-loop additions per second (assuming the accumulator fits in a register). So to do 500,000 bignum additions/second, each bignum addition would only require on average the time of 20 normal additions+iterations. Also note that the functions provided are all tail recursive. Racket performs tail-call optimizations which would make these similarly performant to a for loop.