Answer:
No, it is not correct.
Explanation:
Here, the given problem,
17 × 24
∵ 17 = 10 + 7
And, 24 = 20 + 4
Thus, 17 × 24 = (10 + 7)(20 + 4)
= 10 × 20 + 10 × 4 + 7 × 20 + 7 × 4
= 200 + 40 + 140 + 28
= 408
By comparing the above steps and Sebastian's model,
It is clear that he did incorrectly multiply 7 by 20,
i.e. he must write 140 instead of 40 while adding.