if it was me, i would just round up and down wildly and hope to get it in the ball park for the answer
like 11x11x11/9x9x9 to 12x10x11/10x8x9, essentially making one 11 a 12 and one 9 a 10 and the other way making one 11 a 10 and one 9 an 8... and cancel them out to 11/6 which is little less than 2...
with that said, I usually look at the answer choices to see if they are apart enough, then I would even go for canceling two 11 from the top with two nine from bottom and getting 11/9= 1.2ish (vs. the actual 1.8ish) and I take notice of that and pick something close to 1.5!