Final answer:
To compare two numbers, you must determine the place value at which the numbers differ, which can be ones, tens, hundreds, or thousands place. The context of the problem, such as measurements or significant figures, can indicate the importance of certain digits and where to round off.
Step-by-step explanation:
To determine which place value you need to compare to find the answer in a number comparison, you must look at where the numbers differ for the first time when read from left to right. For instance, if you were comparing 245 to 267, the first place they differ is the tens place. However, if this were not specified in the problem, you compare starting from the leftmost digit and move right until the digits differ, which could be the ones place, tens place, hundreds place, or even the thousands place.
When dealing with measurements or significant figures, the importance of zeros and rounding can determine which digit is significant when comparing values. You often have to look at the context of the problem to determine the correct place value. For example, in the subtraction of 78,500 m - 362 m, since the first measurement is known only to the hundreds place, you would round the result to the same place, which means the correct result is 78,100 m.