1. 101 * 99-100 and 1 / 2 * 99 and 1 / 2
101 * 99-100 and 1 / 2 * 99 and 1 / 2
=(100+1)(100-1)-(100+1/2)(100-1/2)
=10000-1-(10000-1/4)
=-1+1/4
=-3/4
1/1*2+1/2*3+…… +1/99*100+1/100*101=?
The ball is broken!
1/(1×2)+1/(2×3)+...+1/(99×100)+1/(100×101)
=1-1/2+1/2-1/3+...+1/99-1/100+1/100-1/101
=1-1/101
=100/101
Teach me a math problem. It's urgent
a+0=?a-0=?a-a=?ax0=?1/a=?a/a=?0/a=
Note: a divisor is not equal to 0
a+0=a a-0=a a-a=0 ax0=0 1/a=1/a a/a=1 0/a=0
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