When you want to collaborate with others, but do not want to reveal the formulae of your spreadsheet to them, you have a number of options.
Firstly, consider using Google forms instead of sharing your spreadsheet. I discussed using forms to collect data in this previous post.
Secondly, you can allow others to view all, or a part of, your spreadsheet without exposing the formulae, by publishing to the web. Use File > Publish to the web to create a read-only version, as I discussed here.
Finally, you can create a separate spreadsheet for your collaborators to see by using IMPORTRANGE, as described in this post. This lets you to dynamically insert the values (but not the formulae) in a range of cells from one spreadsheet to another.