150-(100-99+98-97+...-3+2-1)
= 150 - ((100-99)+(98-97)+...+(4-3)+(2-1))
=150 - (1.50)
= 100
P/s: k chắc!
\(D=150-\left(100-99+98-87+...+4-3+2-1\right)\)
\(\Rightarrow D=150-\left[\left(100-99\right)+\left(98-97\right)+...+\left(4-3\right)+\left(2-1\right)\right]\)
\(\Rightarrow D=150-\left(1+1+...+1+1\right)\)
\(\Rightarrow D=150-\left(1\cdot50\right)\)
\(\Rightarrow D=150-50\)
\(\Rightarrow D=100\)