The value is 20. 10^2 = 100 and 5^1 = 5. 100/5=20
37+y=87
y=87-37
y=50
............................
7. q+18 =22
q+18-18 =22-18 , q=4
at the problem q+18-18=22+18 mistake (should be subtracted from both sides)
8. r+10-10=22-10 r=12
r-15+15=5+15 r=20
r-18+18=14 +18 r=32
r+5-5=15-5 r=10
I would go with either NIST or SIKG. I put SIKG because the abbreviation for mass is kg and you r look for the SI unit of mass and then the SI stands for International System of units. So when you put both SI And KG (kilograms=mass) it makes SIKG.
This is probably not right but I tried.
Good Luck!