来 / 多 / 把【lái / duō / bǎ】

来, 多 and 把 turn an exact number into an approximate one. 来 is "about", 多 is "more than", and 把 is a casual "or so".

多 before or after the measure word

After a round number – 十, 二十, 一百 – 多 goes before the measure word, and the extra is whole units: 三十多个人 "thirty-odd people". After a number from one to nine, 多 goes after the measure word, and the extra is a fraction of one unit: 一个多小时 "an hour and a bit".

So 十多斤 is anywhere from eleven to nineteen jin, and 十斤多 is ten jin and a bit.

• × 十个多人 → 十多个人
• × 三多个小时 → 三个多小时

来: about, either side

来 follows a round number and means "around", a little over or a little under. It doesn't go after one to nine.

• × 五来个 → 五个左右

把: "or so", in speech

把 follows 个, 百 or 千 directly, with no 一 in front: 个把月 "a month or so", 百把人 "a hundred or so people".

左右 and neighbouring numbers

左右 after the number also means "around", and two neighbouring numbers together, 三四个, mean "three or four". Neither combines with 来 or 多.

• × 二十多个左右 → 二十多个 / 二十个左右