How to add multiple "calculated columns" in Power Query?

For Example, I want to add 2 columns using power Query by making a measure of subtraction on 4 columns from my CCL table. Let I have these 4 columns:

MAT Value 19        MAT Value 18           MTH 19        MTH 18

I want to calculate:

MAT Diff= [MAT Value 19] - [MAT Value 18]

MTH Diff= [MTH 19] - [MTH 18]

i.e, I want to use the following query for multiple subtractions.

= Table.AddColumn(#"Changed Type1", "Subtraction", each [MAT_VALUE_19] - [MAT_VALUE_18], type number)