Oh, dude, rounding numbers is like the easiest math out there. So, 40 rounded to the nearest 10 is... drumroll, please... 40! Yeah, it's already a multiple of 10, so it doesn't need to change. Math can be a breeze when you're as chill as me.
Well, honey, 40 rounded to the nearest 10 is still 40. You can try all you want, but that number isn't budging. It's like trying to squeeze into those jeans from high school - it's just not happening.
When rounding a number to the nearest 10, you look at the digit in the tens place. In this case, the digit in the tens place is 4. Since 4 is less than 5, you round down. Therefore, 40 rounded to the nearest 10 is 40.