To complete this lesson, complete the following tasks:

1. Study the lesson for mastery.

2. Memorize the lesson that it may be recited.

3. Review lessons 1 and 2.

4. Complete the lesson assessment.

## Lesson

1. What are we studying in Article 3 of Modern Arithmetic III?

**In Article 3 of Modern Arithmetic III, we are studying units of the first order, which are simply called “units”.**

2. What do we call a unit?

**A unit is a single thing, called “one”. **

3. How do we signify the number one in Arabic notation?

**In Arabic notation, we signify the number one with the figure 1. **

4. What do we mean by the number “two”?

**One unit and one more are two.**

5. How do we signify the number two in Arabic notation?

**In Arabic notation, we signify the number two with the figure 2. **

6. What do we mean by the number “three”?

**Two units and one more are three.**

7. How do we signify the number three in Arabic notation?

**In Arabic notation, we signify the number three with the figure 3. **

8. What do we mean by the number “four”?

**Three units and one more are four.**

9. How do we signify the number four in Arabic notation?

**In Arabic notation, we signify the number four with the figure 4.**

10. What do we mean by the number “five”?

**Four units and one more are five.**

11. How do we signify the number five in Arabic notation?

**In Arabic notation, we signify the number five with the figure 5.**

12. What do we mean by the number “six”?

**Five units and one more are six.**

13. How do we signify the number six in Arabic notation?

**In Arabic notation, we signify the number six with the figure 6.**

14. What do we mean by the number “seven”?

**Six units and one more are seven.**

15. How do we signify the number seven in Arabic notation?

**In Arabic notation, we signify the number seven with the figure 7.**

16. What do we mean by the number “eight”?

**Seven units and one more are eight.**

17. How do we signify the number eight in Arabic notation?

**In Arabic notation, we signify the number eight with the figure 8.**

18. What do we mean by the number “nine”?

**Eight units and one more are nine.**

19. How do we signify the number nine in Arabic notation?

**In Arabic notation, we signify the number nine with the figure 9.**

20. Why are these nine characters called “significant figures”?

**These nine characters are called significant figures, because they denote something.**

21. What is signified by the character 0?

**The character 0, called zero, stands for nothing; its use is to fill vacant orders. **

22. What does a figure represent when it stands alone or in the first place at the right of a number?

**When a figure stands alone or in the first place at the right of a number, it represents one or more units of the first order.**

23. What are units of the first order called?

**Units of the first order are called simply “units”.**

24. What is the place units occupy called?

**The place units occupy is called “the units’ place”.**