C=1.3.5.7...99 
=>2.4.6...100.C=1.2.3...100 
=>C = (1.2.3....100) / (2.4.6...100)= (1.2.3...50).(51.52...100) / [(2.1)(2.2).(2.3)...(2.50)] 
C=(1.2.3...50).(51.52...100) /[2^50.(1.2.3...50)] =(51.52...100)/2^50 =51/2.52/2.53/2...100/2 =D 
VAy C=D

-->C=\(\frac{1.2.3.4...99.100}{2.4.6....100}\)-->C=\(\frac{1.2.3...99.100}{\left(2.2....2\right)\left(1.2.3.4.5....50\right)}\)[50 chữ số 2]
-->\(C=\frac{51}{2}.\left(\frac{52}{2}\right)....\left(\frac{100}{2}\right)\)=D vậy C=D
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LI-KE CHO MK NHÉ BN 

bạn lên mạng tra là thấy

\(24\cdot55+5^2\cdot53\)

\(=24\cdot55+25\cdot53\)

\(=1320+1325\)

\(=2645\)

24 x 55 + \(5^2\)x 53

= 1320 + 25 x 53

= 1320 + 1325

=   2645

\(24.55+5^2.53\)

\(=24.55+25.53\)

\(=24.55+\left(24+1\right).53\)

\(=24.55+24.53+53\)

\(=24\left(55+53\right)+53\)

\(=24.108+53\)

\(=2645\)

\(62\cdot10:\left\{780:\left[103-\left(2\cdot53+35\cdot14\right)\right]\right\}\)

\(=62\cdot10:\left\{780:\left[103-596\right]\right\}\)

\(=620:\dfrac{-780}{493}\)

\(=620\cdot\dfrac{-493}{780}=\dfrac{-15283}{39}\)