The answer is 3. Divide 5375 by 4 to get 1343.75. Remainder for each friend is .75, so multiply .75 by 4. 3 cards left over.
When you round; you round down if the number in the selected column is below 5 and you round up if the number is 5 and above.
Thus; if you apply this to your question:
784,072 then round up and you get 790,000
Here is the work for this equation:
2+9-x/4 =10
11-x/4=10
11-x=40
x=29