64.84, rounded to the nearest whole number, would be 65.
The rules for rounding are simple: if the number is less that or equal to 4, you round down. If the number if greater than or equal to 5, you round up. Since 8 is greater than 5, you'd round 64 to 65.
However, the answers can vary given different decimals. Let's say you're number is 64.48 and you were told to round. Even though the first decimal space is 4, you'd round 4 to 5 because of the 8 that comes after it. Since it would then be 5, you'd still round up.
