\(9-8+7-6+5-4+3-2+1-0\)
\(=\left(9-8\right)\)\(+\left(7-6\right)\)\(+\left(5-4\right)\)\(+\left(3-2\right)\)\(+\left(1-0\right)\)
\(=1+1+1+1+1=1x5=5\)
815 – 23 – 77 + 185
= ( 815 + 185 ) - ( 23 + 77 )
= 1000 - 100
= 900
a 9 - 8 + 7 - 6 + 5 - 4 + 3 - 2 + 1 - 0
= 1 + 1 + 1 + 1 - 0
=4
b 815 - 23 - 77 + 185
=(815 + 185 ) - (23+ 77 )
= 1000- 100
=900
Ko bt đúng ko