Round number to the place of the ungerline digit 6333 under line is 6

When you round you look at the number to it's left. In this case it is 3. If the number is 4 and below you change it and all other number to its left to 0. If the number is 5 or more you add 1 to the number to its right then change all to its left to 0. In this case the number to the left of 6 is 3, 3 is lest than 4 so it will be 6000

The linear equation is: y=ax+b