a scale (not the kind your thinking of)

a question i ask my patients is, "on a scale of 1 to 10, with 10 being the best and 0 being the worst, where would you rate yourself". i could ask this in relation to anything really ie. energy, stress, congestion, cramps, pain, acne etc.... 

last night, aidan's eyes were acting up. allergies. his left eye was so red (ie. 10/10 for most red i'd ever seen). he could NOT stop rubbing it, which of course made it worse. he said it felt like "100 bee stings in his eyes."
so we worked with this number system.
i first gave him a cool cloth and asked how many bees were in his eye now. 87. getting better.
we continued with the cloth and gave him a homeopathic remedy, allium cepa (i chose this over apis mellifica, because of the intense need to rub, watery discharge and lack of swelling). down to 69.
5 minutes later i gave him a second dose of allium. 40 bee stings now and a smile.
by bed, he proudly announced there were no bees left in his eyes. phew.
is there a system you use with your kids to quantify pain?