 
<translate> Matias rere akwụkwọ 7 * 3 = 21 na Wenezde, ebe ọ rere akwụkwọ okpukpu atọ karịa na Tuesday. Ahịa sitere na Wednesde ji okpukpu atọ rịa elu na Tọzdee, nke pụtara na Matias rere akwụkwọ 21 * 3 = 63 n'oge ahụ. Nke ahụ pụtara na Matias rere akwụkwọ 7 + 21 + 63 = 91 n'ụbọchị atọ ndị a. Azịza ikpeazụ ya bụ: 91. <eng> Matias sold 7 * 3 = 21 books on Wednesday, as he sold three times more books than on Tuesday. The sales from Wednesday were tripled on Thursday, which means Matias sold then 21 * 3 = 63 books. That means in total Matias sold 7 + 21 + 63 = 91 books during these three days.
The final answer: 91. 