1) Numbers are divisible by 10 if they end in 0, by 5 if they end in 0 or 5, and by 2 if they end in 0, 2, 4, 6, or 8.
2) To check divisibility by 3, add the digits and check if the sum is divisible by 3.
3) To check divisibility by 6, check if the number is divisible by both 2 and 3.
4) To check divisibility by 4, check if the last two digits are divisible by 4 for numbers with 3 or more digits.