Nambarada tobanle ee dhamman waxaa loo yaqaan jajab jajab tobanle, sababtoo ah waxay matalaan kala duwan ee jajabyada leh awoodda toban ee hooseeye. Waa sidaas oo kale:
$$\frac{z}{n} = \frac{q_1}{1} + \frac{q_2}{10} + \dots + \frac{q_k}{10^k}$$
leh \(k \in \mathbb{N}\) iyo \(q_k\) \(k-1\) -th meesha midig ee ka dambeeya comma.
Hadda waa:
$$\frac{z}{n} = \frac{10^k \cdot q_1 + 10^{k-1} q_2 + \dots + q_k}{10^k} = \frac{10^k \cdot q_1 + 10^{k-1} q_2 + \dots + q_k}{2^k \cdot 5^k}$$
Tani waxay ka dhigan tahay: Haddii hooseeyaha la kordhin karo ilaa \(2^k \cdot 5^k\) jajab guud oo si dhammaystiran loo soo gaabiyey \(\frac{z}{n}\) , waa jajab jajab tobanle ah oo kooban. . Haddaynu tixgalino qodobka ugu muhiimsan ee hooseeyaha \(n = p_1^{l_1} \cdot \, \dots \, \cdot p_j^{l_j}\) , ka dib marka la eego aragtida aasaasiga ah ee xisaabinta, tan waxaa lagu muujin karaa sida \(f = 2^{km} \cdot 5^{kn}\) ilaa \(2^k \cdot 5^k\) haddii \(n = 2^m \cdot 5^n\) . Tani waxay khuseysaa:
Kaliya jajabyada hooseeyaashooda aysan lahayn arrimo muhim ah oo aan ka ahayn 2's ama 5's marka si buuxda loo soo gaabiyo waxay keenaan jajab jajab tobanle ah.