I agree with Chris Engelsma’s comment (because I thought that I was downloading an answer key to every problem). Certainly something is better than nothing, and to be able to access any curriculum for free is wonderful, but for me to have the time to use Ray’s Arithmetic, I would need to have a full answer key rather than have to compute every answer myself.
“If 12 horses can be sustained in a pasture for 10 months, how many horses will it feed for 1 month?” It can feed 10 times 12 horses for 1 month so 120 horses for 1 month.
Ray's Arithmetic 
What good is this key when it only gives some of the answers?
I agree with Chris Engelsma’s comment (because I thought that I was downloading an answer key to every problem). Certainly something is better than nothing, and to be able to access any curriculum for free is wonderful, but for me to have the time to use Ray’s Arithmetic, I would need to have a full answer key rather than have to compute every answer myself.
May I know what is the answer for no. 12 on page 33 Ray Arithmetic for Grade 3 and 4 ?
If 12 horses can be sustained in a pasture 10 months, how many horses will it feed 1 month?
“If 12 horses can be sustained in a pasture for 10 months, how many horses will it feed for 1 month?” It can feed 10 times 12 horses for 1 month so 120 horses for 1 month.