Add & Subtract Scientific Notation Worksheets (printable, online ... - Free Printable

Let's solve each of these scientific notation operations step by step. The key idea is to convert numbers to the same power of 10 before adding or subtracting, then express the result in proper scientific notation.

---

1. $ 2.9 \times 10^4 + 3.2 \times 10^4 $

Both have the same exponent: $10^4$

Add the coefficients:

$$
2.9 + 3.2 = 6.1
$$

So,

$$
6.1 \times 10^4
$$

✔ Answer: $ \boxed{6.1 \times 10^4} $

---

2. $ 1.11 \times 10^2 + 2.3 \times 10^4 $

Different exponents: $10^2$ and $10^4$. Convert $1.11 \times 10^2$ to $10^4$:

$$
1.11 \times 10^2 = 0.0111 \times 10^4
$$

Now add:

$$
0.0111 \times 10^4 + 2.3 \times 10^4 = (0.0111 + 2.3) \times 10^4 = 2.3111 \times 10^4
$$

✔ Answer: $ \boxed{2.3111 \times 10^4} $

---

3. $ 1.8 \times 10^4 + 4.12 \times 10^2 $

Convert $4.12 \times 10^2$ to $10^4$:

$$
4.12 \times 10^2 = 0.0412 \times 10^4
$$

Now add:

$$
1.8 + 0.0412 = 1.8412
$$

So,

$$
1.8412 \times 10^4
$$

✔ Answer: $ \boxed{1.8412 \times 10^4} $

---

4. $ 9.5 \times 10^5 + 6.2 \times 10^4 $

Convert $6.2 \times 10^4$ to $10^5$:

$$
6.2 \times 10^4 = 0.62 \times 10^5
$$

Add:

$$
9.5 + 0.62 = 10.12
$$

So,

$$
10.12 \times 10^5
$$

But this is not proper scientific notation (coefficient must be between 1 and 10). Adjust:

$$
10.12 \times 10^5 = 1.012 \times 10^6
$$

✔ Answer: $ \boxed{1.012 \times 10^6} $

---

5. $ 5.91 \times 10^4 + 6.12 \times 10^3 $

Convert $6.12 \times 10^3$ to $10^4$:

$$
6.12 \times 10^3 = 0.612 \times 10^4
$$

Add:

$$
5.91 + 0.612 = 6.522
$$

So,

$$
6.522 \times 10^4
$$

✔ Answer: $ \boxed{6.522 \times 10^4} $

---

6. $ 3.32 \times 10^6 - 4 \times 10^6 $

Same exponent: $10^6$

Subtract coefficients:

$$
3.32 - 4 = -0.68
$$

So,

$$
-0.68 \times 10^6
$$

Convert to proper scientific notation:

$$
-0.68 \times 10^6 = -6.8 \times 10^5
$$

✔ Answer: $ \boxed{-6.8 \times 10^5} $

---

7. $ 7.32 \times 10^7 - 3.6 \times 10^6 $

Convert $3.6 \times 10^6$ to $10^7$:

$$
3.6 \times 10^6 = 0.36 \times 10^7
$$

Subtract:

$$
7.32 - 0.36 = 6.96
$$

So,

$$
6.96 \times 10^7
$$

✔ Answer: $ \boxed{6.96 \times 10^7} $

---

8. $ 4.2 \times 10^4 - 3 \times 10^2 $

Convert $3 \times 10^2$ to $10^4$:

$$
3 \times 10^2 = 0.03 \times 10^4
$$

Subtract:

$$
4.2 - 0.03 = 4.17
$$

So,

$$
4.17 \times 10^4
$$

✔ Answer: $ \boxed{4.17 \times 10^4} $

---

9. $ 1.2 \times 10^2 - 2.3 \times 10^3 $

Convert $1.2 \times 10^2$ to $10^3$:

$$
1.2 \times 10^2 = 0.12 \times 10^3
$$

Subtract:

$$
0.12 - 2.3 = -2.18
$$

So,

$$
-2.18 \times 10^3
$$

✔ Answer: $ \boxed{-2.18 \times 10^3} $

---

10. $ 2.02 \times 10^4 + 2.2 \times 10^5 $

Convert $2.02 \times 10^4$ to $10^5$:

$$
2.02 \times 10^4 = 0.202 \times 10^5
$$

Add:

$$
0.202 + 2.2 = 2.402
$$

So,

$$
2.402 \times 10^5
$$

✔ Answer: $ \boxed{2.402 \times 10^5} $

---

✔ Final Answers Summary:

| Problem | Answer |
|--------|--------|
| 1 | $6.1 \times 10^4$ |
| 2 | $2.3111 \times 10^4$ |
| 3 | $1.8412 \times 10^4$ |
| 4 | $1.012 \times 10^6$ |
| 5 | $6.522 \times 10^4$ |
| 6 | $-6.8 \times 10^5$ |
| 7 | $6.96 \times 10^7$ |
| 8 | $4.17 \times 10^4$ |
| 9 | $-2.18 \times 10^3$ |
| 10 | $2.402 \times 10^5$ |

Let me know if you'd like a printable version or explanation for any specific one!