What are the steps to find ROI AND ROE for Target corp?

*look up target financials*

ROI

2017-2018: 13.15%

2016-2017: 11.64%

2015-2016: 13.12%

ROE

2017-2018: 26.03%

2016-2017: 23.70%

2015-2016: 24.76%

below :

date, TTM net income, LT investment and debt, ROI

\begin{tabular}{|cccc} \hline 20180131 & $4.22B & $22.77B & 19.07% \\ \hline 20171031 & $4.34B & $22.18B & 19.76% \\ \hline 20170731 & $4.55B & $21.76B & 20.50% \\ \hline 20170430 & $4.71B & $21.90B & 20.76% \\ \hline 20170131 & $4.86B & $21.98B & 20.71% \\ \hline 20161031 & $5.79B & $23.17B & 23.92% \\ \hline 20160731 & $5.61B & $23.64B & 22.69% \\ \hline 20160430 & $5.69B & $25.14B & 22.54% \\ \hline 20160131 & $5.53B & $24.90B & 21.57% \\ \hline \end{tabular}