Answer:
670 animals
Explanation:
First, round both numbers to the nearest ten. Remember that the numbers 4 and under round down (e.g. 143 = 140) and the numbers 5 and above round up (e.g. 145 = 150).
218 = rounds up = 220
454 = rounds down = 450
Finally, add the rounded numbers together.
220 + 450 = 670
The zoo has approximately 670 animals.