can anyone explain this calculation? im getting a different result$Hi{n}_{,N}=10{\displaystyle \underset{373\mathrm{.}15}{\overset{423\mathrm{.}15}{}}}6\mathrm{.}5+1\mathrm{.}25{10}^{-3}TdT$

$H_{10,N_2}=3499$