The two equations solved by Nate are 3 x 5 = 15 and 15 ÷ 5 = 3.
Nate's method work because both equations are similar. in 3 x 5 = 15, when 3 goes to other side of equation then 15 will be divided by 5 and it gives the answer 3. and second thing the digits in both are same that is 3, 5 and 15.
if we divide 15 by 5, we will get the answer 3.