Question

Ben is 140cm tall.mike is 1090mm tall. who is taller? how much taller?

Answer 1

1090 mm = 109 cm ⇒ Ben is taller
140-109=31 cm <-- this much

Answer 2

Ben is taller, 1090mm into m = 109cm 
$\left[\begin{array}{ccc}1&^{3} 4& ^{10} 0\\1&0&9\\\\&3&1\end{array}\right]$ so 31cm taller