6400 ÷ 7 = 914 R2
Let's divide 6400 by 7.

Step 1:
7 goes into 6 0 times with a remainder of 6.
Write down 0 as next digit of of the result. 
Result so far: 0
Subtract 0 from 6 to get 6.
Bring next digit (4) of the dividend behind the 6 and repeat the process: 64 / 7

Step 2:
7 goes into 64 9 times with a remainder of 1.
Write down 9 as next digit of of the result. 
Result so far: 9
Subtract 63 from 64 to get 1.
Bring next digit (0) of the dividend behind the 1 and repeat the process: 10 / 7

Step 3:
7 goes into 10 1 times with a remainder of 3.
Write down 1 as next digit of of the result. 
Result so far: 91
Subtract 7 from 10 to get 3.
Bring next digit (0) of the dividend behind the 3 and repeat the process: 30 / 7

Step 4:
7 goes into 30 4 times with a remainder of 2.
Write down 4 as next digit of of the result. 
Result so far: 914
Subtract 28 from 30 to get 2.

The final result is 914 with a remainder of 2.