NEW WORK ZERO IN SUBTRACTION SUBTRACTION WITH ZERO 37 30. Zero in Subtraction. (A SILENT READING LESSON.) You can learn many things from this book without the help of your teacher. When you come to a Silent Reading Lesson like this one, study it hard; read carefully and try to understand everything in the lesson. Start in right now to show your teacher that you can study and learn arithmetic by yourself. She will ask you some questions about this lesson later to see if you have really studied. Subtract: 3 0 You know that O is called zero and means not any at all. What do you think the example at the left means? It means that you are to subtract or take nothing from 3. Do you know what the answer is? It is 3, because if you take zero (or nothing) away from 3, you will have 3 left, won't you? Do you know the answers to these nine examples? 10. If you had only 4 cents and you spent them all, how many cents would you have left? You wouldn't have any cents left, would you? You might say this same thing in other ways. Here are two other ways to say it: (a) I would have no cents left. (b) I would have zero cents left. You could show it this way. Had 4 cents Spent 4 cents Do you see that if you subtract 4 from 4 the answer is 0? 11. Make up another problem like number 10 and give it to the class. Don't use cents in your problem. Use apples, sticks of candy, or other things. Can you give the answers to Examples 12 to 20? Facts. (RAPID ORAL 31. The 100 Subtraction DRILL.) Here are the 100 subtraction facts which you need to learn. Can you say them without making a mistake? If you cannot give the answers quickly, turn to pages 370 and 371 and practice until you can. 32. Mixed Addition and Subtraction Practice. (WRITTEN WORK.) Do you like to take tests? This test will give you a chance to show that you know when to add and when to subtract. do neat work. Copy and write the answers: Remember to 8. Find the sum of 6 and 8. 9. What is the difference of 9 and 15? Write these examples and show the signs that belong where the question marks are. This is a question Number 16 shows how to do it. mark: ? NEW WORK SUBTRACTION WITH TWO-FIGURE NUMBERS 33. Learning How to Subtract with Larger Numbers. (WRITTEN WORK.) The problems and questions below will show you how to subtract with larger numbers. (A) HOW MANY ARE LEFT? 1. Tom had a stand and sold popcorn and bottles of pop on circus day. He had 72 bottles of pop one morning. During the day he sold 51 bottles. How many had he left? 72 51 21 To get the answer, you know you must subtract. This is the way to do it: Write the 72 first. Then write the 51 under it. Subtract just as you always have, writing the 1 under the 1 and the 2 under the 5. Tom had 21 bottles left. When you want to subtract one number from another, write the larger number first and write the smaller number under it. Then subtract. |