Hey and welcome on the community forums! 
Like @eran said, る１ means ichidan verb (in some books called る verb or group 2 verbs), while る５ means godan verb with る ending (or う verb with る ending or group 1 verb with る ending).
Basically, ichidan verbs most often end with -いる (-iru) or -える (-eru) like 食べる、見る.
All other verbs ending with る are godan. (except する and くる)
Though there are some exceptions, like 帰る (but 変える is ichidan)、 切る (but 着る is ichidan)、いる which are godan verbs.
They differ in the way they are conjugated. In ichidan verbs in only る ending is dropped and a suffix is attached directly.
- Negative form 食べない
- Stem form 食べます
- Dictionary form 食べる
- Conditional form 食べれば
- Volitional form 食べよう
In godan verbs, the last vowel is changed depending on conjugation and then suffix is added. All five consonants are used for various conjugations, あ、い、う、え、お。
- あ vowel for negative form 帰らない
- い vowel for stem form 帰ります
- う vowel for dictionary form 帰る
- え vowel for conditional form 帰れば
- お vowel for volitional form 帰ろう
I hope it helps,
Cheers! 
