How to Identify Whether a Number is Divisible by 4 and 8

Multiple of 4

Below is a list of the first 50 multiples of 4. From the list, we can see that, the first two digits of the numbers repeat after 100.

04	08	12	16	20
24	28	32	36	40
44	48	52	56	60
64	68	72	76	80
84	88	92	96	100
104	108	112	116	120
124	128	132	136	140
144	148	152	156	160
164	168	172	176	180
184	188	192	196	200

Therefore, we can conclude that

If the first two digits of a number is a multiple of 4, then the number if a multiple of 4.

For example,
Is 2973648 a multiple of four?

The first 2 digits of the number is 48, and 48 is a multiple of 4, hence 2973648 is a multiple of 4.

Let's see another example:
Is 987654324682 a multiple of four?

The first 2 digits of the number is 82, and 82 is not a multiple of 4, hence 987654324682 is not a multiple of 4.

Multiple of 8

A similar rule can be applied to identify the multiple of 8.

If the first three digits of a number is a multiple of 8, then the number if a multiple of 8.

For example,
Is 2973648 a multiple of eight?

The first 3 digits of the number is 648, and 648 is a multiple of 8, hence 2973648 is a multiple of 8.

Let's see another example:
Is 987654324682 a multiple of four?

The first 3 digits of the number is 682, and 682 is not a multiple of 8, hence 987654324682 is not a multiple of 8.