Let's solve the problem step by step based on the worksheet titled
"DOUBLES +1".
---
🔍 Understanding the Concept: "Doubles + 1"
The worksheet teaches a strategy for adding two numbers that are
one apart (like 3 and 4, or 5 and 4). The rule is:
> When the addends are one number away,
double the smaller number and add one more.
So:
- Find the
smaller number.
-
Double it (add it to itself).
- Then
add 1 to get the final sum.
This is called
"doubles plus one".
---
✔ Example Given in Worksheet
Look at the first example:
-
3 + 4
- Smaller number:
3
- Double it: 3 + 3 =
6
- Add 1: 6 + 1 =
7
- So, 3 + 4 =
7
Another example:
-
5 + 4
- Smaller number:
4
- Double it: 4 + 4 =
8
- Add 1: 8 + 1 =
9
- So, 5 + 4 =
9
These match the answers shown in the boxes.
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🧩 Now Solve the Problems Below
We’ll go through each problem using the same method.
---
####
1. 2 + 3
- Smaller number:
2
- Double it: 2 + 2 =
4
- Add 1: 4 + 1 =
5
- So, 2 + 3 =
5
Write:
- Doubles fact:
2 + 2 = 4
- Doubles +1:
2 + 3 = 5
---
####
2. 1 + 2
- Smaller number:
1
- Double it: 1 + 1 =
2
- Add 1: 2 + 1 =
3
- So, 1 + 2 =
3
Write:
- Doubles fact:
1 + 1 = 2
- Doubles +1:
1 + 2 = 3
---
####
3. 3 + 4
- Smaller number:
3
- Double it: 3 + 3 =
6
- Add 1: 6 + 1 =
7
- So, 3 + 4 =
7
Write:
- Doubles fact:
3 + 3 = 6
- Doubles +1:
3 + 4 = 7
---
####
4. 4 + 5
- Smaller number:
4
- Double it: 4 + 4 =
8
- Add 1: 8 + 1 =
9
- So, 4 + 5 =
9
Write:
- Doubles fact:
4 + 4 = 8
- Doubles +1:
4 + 5 = 9
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✔ Final Answers:
| Problem | Smaller Number | Doubles Fact | Doubles +1 |
|--------|----------------|--------------|------------|
| 2 + 3 | 2 | 2 + 2 = 4 | 2 + 3 = 5 |
| 1 + 2 | 1 | 1 + 1 = 2 | 1 + 2 = 3 |
| 3 + 4 | 3 | 3 + 3 = 6 | 3 + 4 = 7 |
| 4 + 5 | 4 | 4 + 4 = 8 | 4 + 5 = 9 |
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💡 Why This Strategy Works
It helps students use known facts (doubles) to solve harder problems quickly. For example, if you know 4 + 4 = 8, then 4 + 5 is just one more: 9.
This builds number sense and mental math skills!
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✔ Answer Key for the Worksheet:
-
2 + 3:
- Doubles fact: 2 + 2 = 4
- Doubles +1: 2 + 3 = 5
-
1 + 2:
- Doubles fact: 1 + 1 = 2
- Doubles +1: 1 + 2 = 3
-
3 + 4:
- Doubles fact: 3 + 3 = 6
- Doubles +1: 3 + 4 = 7
-
4 + 5:
- Doubles fact: 4 + 4 = 8
- Doubles +1: 4 + 5 = 9
Let me know if you'd like this turned into a printable answer sheet!
Parent Tip: Review the logic above to help your child master the concept of doubles and doubles plus one worksheet.
