Round the 3 or 4 digit numbers to the nearest 100 both up and down, and then circle or highlight the closer of the two values to round to the nearest 100.

e.g.  4300  4379  4400 

Next move on to Integer Rounding to Nearest 100 for rounding directly to the nearest 100 without the intermediate step of rounding up and down, or to Round Up and Down to Nearest 1000 to practice rounding larger numbers.