Thus,

II. When a letter is followed by another of greater value, the value of the smaller is to be subtracted from that of the greater. IV = 4; IX = 9; XL = 40; XC = 90; CM = 900.

III. When a letter is placed between two letters of greater value, the value of the smaller is to be subtracted from the sum of the other

10. A book has twenty chapters. Write them in order.

V. A bar placed over a number multiplies it by 1000. Thus, V:

=

The process of uniting two or more numbers to form one number is called addition.

The numbers to be added are called the addends.

The result of addition is called the sum or the amount.

Add, observing the groups that make 5, 10, 15, 20, etc.:

Write from dictation; then add and test, observing

Numbers applied to the same kind of unit are called like numbers; as, 3 ft. and 5 ft., or 3 and 5; but not 3 ft. and 5¢. Only like numbers can be added or subtracted.

Time yourself in adding these examples. Then try again and see whether you can beat your first record.

The process of finding the difference between two numbers, or of taking one number from another, is called subtraction. Subtraction may also be defined as the process of finding what number must be added to a number to make a given number.

The number from which we subtract is called the minuend; the number subtracted is called the subtrahend; and the answer is called the difference, or the remainder.

9 ;

2. Subtract each of the numbers from 1 to 9 from 69 from 94; from 85; from 76; from 53; from 62; from 41; from 30; from 28; from 77.

In 5 a, 64-3034; 34-6=28. Think, 34, 28.

To test subtraction, add the remainder to the subtrahend.