I teach them to find 10%, divide by 10. Find 1%, divide by 100. Then mix and match and add to find what you need. In your case a 10% and four 1%, if that makes sense. I also teach them to find 50% and 25%, but it isn't relevant for your example. However I'd expect most year 6 children to be able to notice that 14% of 50 must be 7 without any real working.