SECTION II. FUNDAMENTAL PROCESSES. ADDITION. ORAL EXERCISES. 12.-1. A class has 4 boys and 9 girls in it; how many pupils in the class? 2. Horace is 5 years old; how old will he be in 8 years? In 9 years? In 6 years? In 5 years? 3. A farmer has 6 cows; how many will he have if he buys 5 more? 8 more? 7 more? 6 more? 9 more? 4. Arthur has 7 marbles; how many will he have if he buys 5 more? 6 more? 9 more? 8 more? 7 more? 5. Ruth has 8 cents; how many will she have if May gives her 6 more? 5 more? 9 more? 8 more? 7 more? 6. A teacher has 9 pupils in arithmetic; if 9 more are added, how many will there be in the class? If 8 more? If 7 more? If 6 more? If 5 more? If 4 more? 31. 8. Count by 2's from 2 to 30. From 30 to 60. From 1 to From 31 to 61. 9. Count by 3's from 3 to 45. From 1 to 46. From 2 to 47. 12.-1. A class has 4 boys and 9 girls in it; how many 2. Horace is 5 years old; how old will he be in 8 years? In 9 years? In 6 years? In 5 years? 3. A farmer has 6 cows; how many will he have if he buys 5 more? 8 more? 7 more? 6 more? 9 more? 4. Arthur has 7 marbles; how many will he have if he buys 5 more? 6 more? 9 more? 8 more? 7 more? 5. Ruth has 8 cents; how many will she have if May gives her 6 more? 5 more? 9 more? 8 more? 7 more? 6. A teacher has 9 pupils in arithmetic; if 9 more are added, 8. Count by 2's from 2 to 30. From 30 to 60. From 1 to 9. Count by 3's from 3 to 45. From 1 to 46. From 2 to 47. 31. ARITHMETIC. SECTION I. NUMERATION AND NOTATION. 1. If we desire to know how many trees there are in a certain grove, we must count them; thus, one, two, three, four, five, six, seven, eight, nine, etc., until all have been counted. These expressions, one, two, three, etc., are called Whole Numbers, or Integers. 2. Notation is the method of representing numbers by means of characters. Numeration is the method of reading numbers when expressed by characters. ARABIC SYSTEM OF NOTATION. 3. Ten characters, called Figures, are used to represent numbers. They are― FIGURES, 1, 2, 3, 4, 6, 7, 8, 9, 0, six, seven, eight, nine, zero. These ten characters are also called Digits. A figure standing alone expresses ones, or Units. 4. Numbers greater than nine are expressed by writing two or more of these figures side by side. If we add one more to nine, we shall have ten. To express this, we write 1 in the second place and zero in the first place. Hence A figure standing in the second place expresses Tens. Thus, 10 is ten units or 1 ten, called ten. 11 is 1 ten and 1 unit, or eleven. And so on to 19, or nineteen. 20 is 2 tens, called twenty. 21 is 2 tens and 1 unit, or twenty-one. And so on to 29, or twenty-nine. In like manner we have 30, 40, 50, 60, 70, 80, 90, with the intervening numbers. EXERCISES. 1. Write neatly in figures the numbers from ten to twenty; from thirty to forty; from fifty to sixty; from seventy to eighty; from thirty-four to fifty-six; from sixty-six to eighty-six. 9. What is the largest number that can be expressed by two figures? What is the smallest? |