We can test various whole numbers and multiply them by 3 to see how close we can get to 53. 17 multiplied by 3 is 51, while 18 multiplied by 3 is 54. Since 53 is between 51 and 54, this means that 53/3 is between 17 and 18.
Furthermore, since 53 is closer to 54 than to 51, dividing it by 3 would put it closer to 18 than to 17.
