When I was in grade school, I used to imagine that the numbers had personalities and relationships—which made solving equations more fun. The function, addition, subtraction, etc., indicated what kind of action one number was taking against another.
5 was in love with 4, who loved him back. 7 was a bitch who wanted 5 for herself and was therefore always a jerk to 4. 6 was grumpy and disinterested in the whole drama but kept getting roped in because he’s a stand-up guy. 1, 2, and 3 were too young to care but sometimes served as Macbethian witches. 8 was 7’s spurned boyfriend who decided he had more in common with 4. 9 was like everyone’s big sister and the only person 7 was afraid of.
These ditties certainly made standardized testing more interesting.