To round 423 to the nearest ten, we look at the digit in the tens place, which is 2. Since the digit to the right of it is 3, which is 5 or greater, we round up. Therefore, 423 rounded to the nearest ten is 430.
423.0
400
420
400
400
Yes
2,900,000
1, 3, 9, 47, 141, 423
I put the larger number above the smaller number and then I subtract. 719 423 ----- 296
423 is a composite number. Its prime factorisation is 3 x 3 x 47.
No, it is not a prime number.