Current location - Training Enrollment Network - Mathematics courses - Math problem in the fourth grade of primary school: "1-2+3-4+5-6 ...+1991992+1993 = ()" How to do this math problem? Seek answers.
Math problem in the fourth grade of primary school: "1-2+3-4+5-6 ...+1991992+1993 = ()" How to do this math problem? Seek answers.
Namely (1+3+5++ 1993)
_(2+4+6+.....+ 1992)
Namely 1+(3+5+7++ 1993)
-(2+4+6+ + 1992)
Observe that the subtraction of the alignment in brackets is 1, so it is1+1x1992 ÷ 2 = 997.