Addition input/output tables – up to two digits
key notes :
Using Input/Output Tables With Two-Digit Addition:
🥊Your favorite arcade is having a special promotion! Any time you buy 20 or more tokens, you get 15 tokens free. You buy 20 tokens. Your three friends buy 32, 48, and 65 tokens. How many tokens do each of you have?
🥏How can we figure out how many total tokens you’d get if you bought 20, 32, 48, or 65 tokens?
Yes! 😀 We will need to add!
🔑 Since we are adding so many numbers, we can keep track of them in input/output tables.
Input/Output Tables
Let’s take a look at what an input/out table is.
Every input/output table has a rule.
🔑 The rule tells us what we have to do to the numbers in the “In” column to get the “Out” column.
Learn with an example
Complete the table.
Rule: add 8
| In | Out |
| 0 | |
| 4 | 12 |
| 5 | |
| 9 |
Start with the numbers in the “In” column. Add 8 to each number.
| 0 | + | 8 | = | 8 |
| 4 | + | 8 | = | 12 |
| 5 | + | 8 | = | 13 |
| 9 | + | 8 | = | 17 |
Write the answers in the table:
| In | Out |
| 0 | 8 |
| 4 | 12 |
| 5 | 13 |
| 9 | 17 |
Complete the table.
Rule: add 3
| In | Out |
| 0 | |
| 9 | 12 |
| 10 | |
| 12 |
solution
Start with the numbers in the “In” column. Add 3 to each number.
| 0 | + | 3 | = | 3 |
| 9 | + | 3 | = | 12 |
| 10 | + | 3 | = | 13 |
| 12 | + | 3 | = | 15 |
Write the answers in the table:
| In | Out |
| 0 | 3 |
| 9 | 12 |
| 10 | 13 |
| 12 | 15 |
Complete the table.
Rule: add 7
| In | Out |
| 2 | |
| 5 | |
| 8 | |
| 11 | 18 |
Start with the numbers in the “In” column. Add 7 to each number.
| 2 | + | 7 | = | 9 |
| 5 | + | 7 | = | 12 |
| 8 | + | 7 | = | 15 |
| 11 | + | 7 | = | 18 |
Write the answers in the table:
| In | Out |
| 2 | 9 |
| 5 | 12 |
| 8 | 15 |
| 11 | 18 |
Let’s practice!🖊️
