问题
解答题
200+199-198+197-196+…+5-4+3-2+1.
答案
200+199-198+197-196+…+5-4+3-2+1,
=200+(199-198)+(197-196)+…+(5-4)+(3-2)+1,
=200+1×[(200-2)÷2]+1,
=200+1×99+1,
=300.
200+199-198+197-196+…+5-4+3-2+1.
200+199-198+197-196+…+5-4+3-2+1,
=200+(199-198)+(197-196)+…+(5-4)+(3-2)+1,
=200+1×[(200-2)÷2]+1,
=200+1×99+1,
=300.