Row 1: 5 coins
Row 2: 2 coins
Row 3: 3 coins
Row 4: 4 coins
Work: let 0 be a coin.
so... :R1 00000 since r2 has 2 coins, then 2+3=5
R2 00 since r3 has 3 coins, then 1-3=2
R3 000 since r2 is 1 less than this row
R4 0000 and since r4 is 2x2
Hope this helped!!
:)