12 3/10 (12 3/10) more than (+) 5 13/1000 of a number d (5 13/1000d) is equal to (=) 15 and 302/1000 so
we want the bottom numbers the same so
12 and 3/10=12 and 300/1000 5 and 13/1000 is the same 302/1000 is the same so
12 300/1000+5 13/1000d=15 302/1000 subtract 12 300/1000 from both sides 5 13/1000d=3 2/1000 5 13/1000d=5013/1000d 3 2/1000=3002/1000 5013/1000(d)=3002/1000 multiply both sides by 1000/5013 (to make it a one exg 1/2 times 2/1=2/2=1)
