Lesson 5: Repetitive Subtraction and Addition
TEACHER’S GUIDE
Lesson 5: Repetitive Subtraction and Addition
Overview | Use the calculator to subtract or add repetitive | ||
| numbers using the constant function. | ||
Teacher Materials | “Repetitive Subtraction and Addition” and “Fastest | ||
| Fingers” transparencies. | ||
Student Materials | Pencil, Calculator, and “Constant Calculations” | ||
| worksheet. | ||
Keys Introduced | Constant function using the = Key. | ||
Teaching Notes | Ask your students to enter 10 on the calculator and | ||
| add 10 to the total every time you snap your fingers. | ||
| Snap your fingers 4 times and compare the answers | ||
| from several students (the answer should be 50). | ||
| Tell the students how the calculator stores the last | ||
| command and number entered. This is called the | ||
| constant function. The constant function helps reduce | ||
| mistakes and save time when you must subtract, add, | ||
| divide, or multiply the same number many times. | ||
| Ask your students to again enter 10 on the calculator | ||
| and add 10 every time you snap your fingers. Snap | ||
| your fingers 4 times and compare the answers. | ||
| Note: The constant is removed from memory when | ||
| the | ON/AC | button is pushed. |
| Use the “Fastest Fingers” transparency to play a fun | ||
| game that reinforces the constant function. | ||
| Use the “Constant Calculations” worksheet for | ||
| practice. | ||
Victor 900 Calculator Teacher’s Guide | 17 |