ArcMap Field Calculator to select values >20 on multiple fields

I need a Field Calculator script to select a feature (trees layer), if values from multiple fields, namely the amount of pine, spruce and birch, meet a specific condition: The values of pine "V101__m_3_", spruce "V201__m_3_" and birch "V302__m_3_" columns have to be at least 20% of the total wood volume column "Vtot__m_3_". The "Vxxx__x__x" is the name of the fields.

The values are integers.

How is this done?

I've tried this, but it doesn't work:

``````"V101__m_3_"+ "V201__m_3_"+ "V301__m_3_"+ "V302__m_3_" > 20/ "Vtot__m_3_"
``````
• It's hard to answer without seeing the actual data, but I notice that you are summing 4 values, rather that 3 (pine, spruce and birch). 20% (i.e. one fifth) of the total value would be `"Vtot__m_3_" / 5` instead of `20 / "Vtot__m_3_"` Oct 19, 2021 at 11:00

``````("V101__m_3_"+ "V201__m_3_"+ "V301__m_3_"+ "V302__m_3_") * 5 > "Vtot__m_3_"
It's actually very hard to answer the question by speculating how your data tree looks like. But I assume that you have three fields for `pine, spruce, and birch`; each has `int` values as a percentage.