Valmiki Ramayana Kishkindha Kanda Sarga 31 Shloka 25

केचित् some, दशनागबलाः possessed the strength of ten elephants, केचित् some, दशगुणोत्तराः of a hundred elephants in strength, केचित् some, नागसहस्रस्य of a thousand elephants in strength, तुल्यविक्रमाः equal in valour, बभूवुः were.

Of them some possessed the strength of ten, some a hundred and some a thousand elephants. All of them were of equal valour.