Question

Chen is checking a division problem by doing the following:

Answer 1

That "+2" is the remainder of a division.  Note that 152 times 4 is 608.
Dividing 608 by 4 results in 152 with no remainder.
Dividing 610 by 4 results in 152 with the remainder 2.
                                                                   ____
Chen is checking the division problem  4 /  610   .