I am trying to figure out NOPAT and struggling with it$.$

Halliburton and Schlumberger compete in the oil field services sector. Refer to the following $2018$ financial data for the two companies to answer the requirements.

$ millions HAL SLB

Total revenue $$24,661$ $$33,481$

Pretax net nonoperating expense $1,3191,092$

Net income $2,3232,843$

Average operating assets $24,02768,502$

Average operating liabilities $6,55417,165$

Marginal tax rate $22\%19\%$

Return on equity $18\mathrm{.}56\%5\mathrm{.}86\%$