350
340
350
It is: 350 to the nearest 10
350
650
350
It is: 350 rounded to the nearest ten
The smallest number to be rounded to 350 would be any number greater than or equal to 345 but less than 355. This is because when rounding to the nearest 10, any number 5 or greater will round up. Therefore, the smallest number that, when rounded to the nearest 10, would result in 350 is 345.
400
350
8 is already rounded to the nearest 10th. Rounded to the nearest 10 is 10.