All whole numbers are divisible by 1.
Numbers are divisible by 2 if they end in 2, 4, 6, 8 or 0.
Numbers are divisible by 3 if the sum of their digits is divisible by 3.
Numbers are divisible by 4 if the last two digits of the number are divisible by 4.
Numbers are divisible by 5 if the last digit of the number is either 5 or 0.
Numbers are divisible by 6 if they are divisible by 2 and 3.
Numbers are divisible by 9 if the sum of their digits is equal to 9 or a multiple of 9.
Numbers are divisible by 10 if the last digit of the number is 0.
12
26
Those for 1, 2, 4, 5 and 8.
Any even number is divisible by 2.
For 2 it's any even number.For 5 it's if the number ends in 5 or 0.For 10 it's if the number ends with a zero. That's basically it.
12
26
Those for 1, 2, 4, 5 and 8.
3 and 9. And they divide into 123456789 whether or not you use divisibility rules!
Divide by two and five. 1, 2, 4, 5, 10, 20
The divisibility rule for 2 works because the base of our number system, 10, is divisible by 2.
2 squared 1 = 4 so the divisibility rule is that it is divisible by 1, 2 and 4.
350 is a composite number. it can be divisible by 10, 35, 5, 2 etc. You will find it easier to tell between prime and composite if you know the divisibility rules. one simple one is that if a number ends with zero it is divisible by 10...there are a lot of other divisibility rules.
Any even number is divisible by 2.
Factors are divisors. If you know the divisibility rules, you know that 80 is divisible by 1, 2, 4, 5 and 8. If you divide 80 by those numbers, you find the other half of the factor pairs.
For 2 it's any even number.For 5 it's if the number ends in 5 or 0.For 10 it's if the number ends with a zero. That's basically it.
You have to use the rules of 4 and 9 Using the rules of 2 and 18 won't work because the smallest common multiple of 2 and 18 is 18 not 36. 3 and 12 won't work either because the smallest common multiple of 3 and 12 is 12 not 36. However 4 and 9 does work because their biggest common divisor is 1 so multiplying them works. The biggest common divisor of 2 and 18 is 2 and the biggest common divisor of 3 and 12 is 3