"Divisible by" means "when you divide one number by another the result is a whole number." For example $77$77is divisible by $7$7 because $77\div7=11$77÷7=11. We could also say that $7$7 and $11$11 are factors of $77$77 (see Breaking Down Numbers for more information on factors).
Remember, we can use our knowledge of multiplication and division to complete sets of related number facts.
$13\times4=52$13×4=52
$4\times13=52$4×13=52
$52\div4=13$52÷4=13
$52\div13=4$52÷13=4
All even numbers are divisible by $2$2.
$28$28 is even, so it is divisible by $2$2.
$28\div2=14$28÷2=14
A number is divisible by $3$3 if the sum of the digits is divisible by $3$3.
$234$234 is divisible by $3$3 since $2+3+4=9$2+3+4=9.
$234\div3=78$234÷3=78
All numbers ending with a $5$5 or a $0$0 are divisible by $5$5.
$85$85 ends with a $5$5, so it is divisible by $5$5.
$85\div5=17$85÷5=17
A number is divisible by $9$9 if the sum of the digits is divisible by $9$9.
$324$324 is divisible by $9$9 since $3+2+4=9$3+2+4=9
$324\div9=36$324÷9=36
All numbers ending in a 0 are divisible by 10.
$5200$5200 ends in a $0$0, so it is divisible by $10$10.
$5200\div10=520$5200÷10=520
Are the following numbers divisible by $4$4?
$58784$58784
Yes
No
$372938$372938
Yes
No
$58832$58832
Yes
No
Which of the following numbers are exactly divisible by 3?
$73500$73500
$73495$73495
$545824$545824
$599772$599772
Are the following numbers divisible by $8$8?
$195992$195992
Yes
No
$1669488$1669488
Yes
No
$1669374$1669374
Yes
No