C. 10r-3
Because 2r+5=7, the minus 6 and 7 which gives you 1 then minus 4 and 1 witch is 3 then you do 10r-3 and it will get you to 2r+5=7 again. I hope this helped!
<span>700 cm
I might be wrong though
have fun with it</span>
8 goes in to 16 2 times so put 2 on the top. 8 x 2 is 16 so do 16 - 16 which is 0. 8 cant go into 0 so put a 0 on top. Bring down the 1; 8 cant go into 1 so bring down the 3. 8 can go into 13 1 time so put a 1 on top. 13 - 8 is 5 so the remainder is 5
Its 18 because you times 6 and 3