Question

简便计算：899998－799999＋89998－79999＋8998－7999＋898－799＋88－79

简便计算

Answer 1

899998－799999＋89998－79999＋8998－7999＋898－799＋88－79
=(899998+1)-(799999+1)+........
=899999-800000+....
=99999+9999+999+99+9
=99999+1-1+9999+1-1...
=100000-1+10000-1+..
=111110-5
=111105

Answer 2

899998－799999＋89998－79999＋8998－7999＋898－799＋88－79
=（900000-800000+90000-80000+9000-8000+900-800+90-80）-5
=111110-5
=111105

Answer 3

899998－799999＋89998－79999＋8998－7999＋898－799＋88－79
=900000-2-800000+1+90000-2-80000+1....
=100000-1+10000-1+1000-1+100-1+10-1
=111110-5
=111105

Answer 4

899998－799999＋89998－79999＋8998－7999＋898－799＋88－79
=99998+(800000-799999)+9998+(80000-79999)+998+(8000-7999)+98+(800-799)+8+(80-79)
=99998+1+9998+1+998+1+98+1+8+1
=99999+9999+999+99+9
=100000-1+10000-1+1000-1+100-1-10-1=111110-5=111105