We have to do it correctly first to check the answer and process.
I'm gonna use the algorithm method
2 7 8
x 2 4
-----------------------------
1 3 3(they go above all 3 1s)
1 1 1 2
1 1( they above above both 5s)
5 5 6 0
---------------
6 6 7 2
They forgot to add a 0 to the 2nd column. Due to this they got the wrong answer. The 0 was meant to go right next to the 556 because you are multiplying in the tens column.
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