400 + 400 + 200 + 10
= 800 + 200 + 10
= 1000 + 10
= 1010
________________________
900 x 1 + 3 x 1 + 8 x 1
= ( 900 + 3 + 8 ) x 1
= ( 903 + 8 ) x 1
= 911 x 1
= 911
400 + 400 + 200 + 10
= 800 + 200 + 10
= 1000 + 10
= 1010
900 x 1 + 3 x 1 + 8 x 1
= 900 + 3 + 8
= 903 + 8
= 911
k nha ^_^
400 + 400 + 200 + 10
= 800 + 200 + 10
= 1000 + 10
= 1010
900 x 1 +3 x 1 + 8 x 1
= 1 x ( 900 + 3 + 8 )
= 1 x 911
= 911