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# Modern Arithmetic III, Article 5

To complete this lesson, complete the following tasks:

1.   Study the lesson for mastery.
2.  Memorize the lesson that it may be recited.
3.  Complete the lesson assessment.

## Lesson

1. How do we express numbers between 10 and 20, 20 and 30, etc.?
The numbers between 10 and 20, 20 and 30, etc., are expressed by representing the tens and units of which they are composed.

2.  What do we call one ten and one unit?
One ten and one unit are called “eleven”.

3.  How is one ten and one unit written?
One ten and one unit is written 11.

4.  What do we call one ten and two units?
One ten and two units are called “twelve”.

5.  How is one ten and two units written?
One ten and two units is written 12.

6.  What do we call one ten and three units?
One ten and three units are called “thirteen”.

7.  How is one ten and three units written?
One ten and three units is written 13.

8.  What do we call one ten and four units?
One ten and four units are called “fourteen”.

9.  How is one ten and four units written?
One ten and four units is written 14.

10.  What do we call one ten and five units?
One ten and five units are called “fifteen”.

11.  How is one ten and five units written?
One ten and five units is written 15.

12.  What do we call one ten and six units?
One ten and six units are called “sixteen”.

13.  How is one ten and six units written?
One ten and six units is written 16.

14.  What do we call one ten and seven units?
One ten and seven units are called “seventeen”.

15.  How is one ten and seven units written?
One ten and seven units is written 17.

16.  What do we call one ten and eight units?
One ten and eight units are called “eighteen”.

17.  How is one ten and eight units written?
One ten and eight units is written 18.

18.  What do we call one ten and nine units?
One ten and nine units are called “nineteen”.

19.  How is one ten and nine units written?
One ten and nine units is written 19.

20.  What do we call two tens and one unit?
Two tens and one unit are called “twenty-one”.

21.  How is two tens and one unit written?
Two tens and one unit is written 21.

22.  What do we call two tens and two units?
Two tens and two units are called “twenty-two”.

23.  How is two tens and two units written?
Two tens and two units is written 22.

## Assessment

Modern Arithmetic III, Article 05 Exam