Quick little project here... As the title says, and as the splash screen says. See this discussion for context: http://scratch.mit.edu/discuss/post/235730/ Enjoy! (But see below for my warnings about this...)
Note that I'm not sure having the exact constructions for powers of ten is a totally great idea... I mean, it's fine to get the 'right' answer for something like 10^17, but it's not a result you can reliably use in many other calculations since it's already beyond the precision of numbers in Scratch (e.g. try subtracting one from it!) See http://scratch.mit.edu/discuss/post/236275/