Three-fifths of a number exceeds two-sevenths of the same number by 44. What is the number?

Let the number be $x$. Then $(3/5)x-(2/7)x=44$. Over the common denominator 35 this is $(21x-10x)/35=44$, i.e. $11x/35=44$, so $x=44\times 35÷11=140$. Check: 84 − 40 = 44. The classic slip is to cancel the 35 by accident and solve $11x=44$, which gives the far too small answer 4.