To round 693 in the tens place, you would need to look at the ten's place. If the number you are rounding to is 5 or high, then the number next to it rounds up. If it was 4 or lower, it would round down. In this case since the number in the ten's place is 9, and the number next to it is 3. Since 3 is lower than 5, you round down 693 to 690.
