Yes, that's a strategy I discussed w/ DS. For ex: 34x12 ... look for an answer that as 8 in the ones place. I told him that later, the kids who know strategies will finish in time b/c they are not bogged down in doing the full calculation. So w/ a strong sense of place value, a kid could answer 34x12 in multiple choice unless the question is written such that all the answers have 8 in the ones place lol. But then you could estimate as well perhaps 30x10 and get in the ballpark.