A) (8978+2859)-1859= 11837 - 1859 = 9978
B) (4937+3887)-4937= 8824 - 4937 = 3887
C) 5836 - (2836+989) = 5836 - 3825 = 2011
D) 8381 - (1623+6381) = 8381 - 8004 = 377
A) (8978+2859)-1859= 11837 - 1859 = 9978
B) (4937+3887)-4937= 8824 - 4937 = 3887
C) 5836 - (2836+989) = 5836 - 3825 = 2011
D) 8381 - (1623+6381) = 8381 - 8004 = 377