Whats the upper bound for estimate for 354 + 267?

whats the lower bound estimate for 63.75 + 3.63?

Personally I'd replace 354 with 360 and 267 with 270, and then add 360 and 270, obtaining 630. Similarly, estimate 63.75 + 3.63 by adding 60 and 3: 63. There's no single answer for either problem. For "upper bound," I round the given addends upward; for "lower bound," I found the addends down.