firstly, because we are rounding to the nearest thousand, look at the digit of the number with the place value of one thousand. The number in this instance is 2.
Next, look to the right of the 2 (the digit with the smaller place value).
There are two possible outcomes when rounding:
A) If the value of this digit is either 0,1,2,3,4, then you do not round up, instead you drop the end of the number after the 2 as so: 642,000.
B) However, if the digit to the right of the left 2 was either a 5,6,7,8, or 9, then you would add one digit to the thousand place value, making the answer: 643,000.
In this case, however, we would use case A) of rounding because the digit in the place value to the right of the thousand place value is a 1.
