Explain how comparing 645 and 738 is a different from comparing 645 and 649

Well one way is their difference in amounts, for instance 645 and 738 have an amount difference of 93. That contrasts with 645 and 649's amount difference that is only 4. They are different because one's difference (645 and 738) is higher/bigger than the other's (645 and 649) or you can flip it and say they're different because one's difference is lower/smaller (645 and 649) than the other's (645 and 738).