I ran across Jim Breen's page (http://nihongo.monash.edu/jnumbers.html) regarding numbers, it links to an image (provided below) which I found confusing.
It reads 112 as ippyakujuuni, and 1386 as sensanbyakuhachijuuroku. I would expect ichihyaku or hyaku, not ippyaku, for 100. And sanhyaku, not sanbyaku, for 300. What is behind this strange reading of 100 there?
There is also similarly strange reading of number 2 036 521 801 in Wikipedia, which is ni-jū oku san-zen rop-pyaku go-jū ni-man sen hap-pyaku ichi. Why san-zen, not san-sen? Why rop-pyaku, not roku-hyaku? Why hap-pyaku, not hachi-hyaku?