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( 248 × 21 ) -m = 87 × 16
( 248 × 21 ) -m = 1.392
5.208 -m = 1.392
m = 5.208 - 1.392
m = 3.816
m + ( 26 × 13 ) = 635
m + 338 = 635
m = 635 - 338
m = 297
