??? wen yu sae 20x21, du yu meen 20*21???
then yu sae dividabel bi [10]^x...this x is a dont-no us spozed tu find?????
20*21*22*...*30=2,180,547,009,000,000,000,000,000 (approx)
kleerly, 10 divide intu 20 & 30, so 100 divide intu produkt
yer number=30 faktorial - 19 faktorial
30!=265,252,859,812,191,058,636,308,480,000,000
19!= 121,645,100,408,832,000
differ=265,252,859,812,190,936,991,208,071,168,000
000 at end tell us kan divide bi 1000