402 ÷ 1 = 402 R0
Let's divide 402 by 1.

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

Step 2:
1 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of of the result. 
Result so far: 40
Subtract 0 from 0 to get 0.
Bring next digit (2) of the dividend behind the 0 and repeat the process: 2 / 1

Step 3:
1 goes into 2 2 times with a remainder of 0.
Write down 2 as next digit of of the result. 
Result so far: 402
Subtract 2 from 2 to get 0.

The final result is 402 with a remainder of 0.