Answer:
The correct answer is B. 30.
Step-by-step explanation:
538 - 509 = 29
Since we need to round this to the nearest tens place, that means we need to round it to 10, 20, 30, etc.
When rounding a number, you look at the last number in it. If it is a <em>5 or higher</em>, you <em>round up</em> the number before it by 1. If it is a <em>4 or lower</em>, the number before it<em> stays the same</em> and the <em>lowest number</em> turns into a 0.
Since 9 is <u><em>higher</em></u> than 5, the 2 in 29 will turn to a 3, and the 9 will turn into a 0.
Therefore, the correct answer is B. 30.
Hope this helps! :D