Hello, I am Yoshi from NILS Japanese language school. We start a new lesson today.
[Saying numbers #1]1) ひとつ, ふたつ・・・・・・とお
These words are used to count things up to ten. Eleven and higher are counted by using the numbers themselves.
ひとつ　1（一）つ：　one
ふたつ　2（二）つ：　two
みっつ　3（三）つ：　three
よっつ　4（四）つ：　four
いつつ　5（五）つ：　five
むっつ　6（六）つ：　six
ななつ　7（七）つ：　seven
やっつ　8（八）つ：　eight
ここのつ　9（九）つ：　nine
とお　10（十）：　ten

2) Counter Suffixes
When counting some sorts of things or expressing the quantity of things, counter suffixes are attached after the numbers.
-人（にん）:　Number of people except for one and two. ひとり（1人／一人） and ふたり（2人／二人） are used for one and two. 4人（four people) is read よにん.
-台（だい）: Number of machines or vehicles like cars and bicycles.
-枚（まい）: Number of thin or flat things such as paper, dish, shirts, CDs, etc.
-回（かい）: times
-分（ふん）: minutes
-時間（じかん）: hours
-日（にち）: days [Note] The number of days takes the counter suffix にち. However, from two to ten, the same words as used for dates are used. “One day” is 1にち, “two days” is ふつか, ・・・・・・, “ten days” is とおか.
-週間（しゅうかん）: weeks
-か[ヶ]月（かげつ）: months
-年（ねん）: years
There are many other counter suffixes.

3) Usage: Quantifiers (numbers with counter suffixes) are usually put before the verbs they modify. However, this is not always the case with length of the time.
(Example)
りんごを　4つ　買いました。　　We bought four apples.
外国人（がいこくじん）の　学生が　2人　います。　　There are two foreign students.
国（くに）で　2ヶ月　日本語を　勉強しました。　　I studied Japanese for two months in my country.
*外国人の：　foreign
*国：　my home country (in above case)

August 8th News, from NILS Japanese language school.