Attachment below to also help but
2 & 1/7 is 15/7 when in a improper fraction
So 15/7 divide 2/7
Now which 2/7 to 7/2 and divded sign now become a multiplication sign
So now we have
15/7 x 7/2 which is 105/14
Then when multiply that becomes 105/14
105 divided by 7/ 14 divided by 2 (since the greatest common factor between 14 and 105 is 7) then when divided that gives 15/2