问题
解答题
计算:
①113×5-37×15=______
②(1+2+3+…+2007+2008+2007+…+3+2+1)÷2008=______.
答案
(1)113×5-37×15
=113×5-37×3×5,
=113×5-111×5,
=5×(113-111),
=10;
(2)(1+2+3+…+2007+2008+2007+…+3+2+1)÷2008
=[(1+2007)+(2+2006)+…+(2007+1)+2008]÷2008,
=2008×2008÷2008,
=2008;
故答案为:10、2008.