[tex]\begin{array}{r|l}112&2\\56&2\\28&2\\14&2\\7&7\\1\end{array}\\\\112=2^4\cdot7\\\\\\\begin{array}{r|l}180&2\\90&2\\45&3\\15&3\\5&5\\1\end{array}\\\\180=2^2\cdot3^2\cdot5\\\\\text{NWD}(112,180)=2^2=4[/tex]
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[tex]\begin{array}{r|l}120&2\\60&2\\30&2\\15&3\\5&5\\1\end{array}\\\\120=2^3\cdot3\cdot5\\\\\\\begin{array}{r|l}980&2\\490&2\\245&5\\49&7\\7&7\\1\end{array}\\\\980=2^2\cdot5\cdot7^2\\\\\text{NWD}(120,980)=2^2\cdot5=20[/tex]
