We are asked to solve several addition and subtraction problems involving numbers in scientific notation.

1. Problem Description

We are asked to solve several addition and subtraction problems involving numbers in scientific notation.

2. Solution Steps

1. $(6 \times 10^4) + (2.55 \times 10^4)$

Since the powers of 10 are the same, we can add the coefficients:

$(6 + 2.55) \times 10^4 = 8.55 \times 10^4$

2. $(8.5 \times 10^7) + (7.25 \times 10^7)$

Since the powers of 10 are the same, we can add the coefficients:

$(8.5 + 7.25) \times 10^7 = 15.75 \times 10^7$

We can rewrite this in proper scientific notation:

$15.75 \times 10^7 = 1.575 \times 10^1 \times 10^7 = 1.575 \times 10^8$

3. $(9 \times 10^{-5}) - (5.4 \times 10^{-5})$

Since the powers of 10 are the same, we can subtract the coefficients:

$(9 - 5.4) \times 10^{-5} = 3.6 \times 10^{-5}$

4. $(3.7 \times 10^9) - (3.205 \times 10^9)$

Since the powers of 10 are the same, we can subtract the coefficients:

$(3.7 - 3.205) \times 10^9 = 0.495 \times 10^9$

5. $(6.15 \times 10^{12}) + (9.8 \times 10^{13})$

We need to make the powers of 10 the same. We can rewrite $6.15 \times 10^{12}$ as $0.615 \times 10^{13}$.

Now we can add:

$(0.615 \times 10^{13}) + (9.8 \times 10^{13}) = (0.615 + 9.8) \times 10^{13} = 10.415 \times 10^{13} = 1.0415 \times 10^{14}$

6. $(4.39 \times 10^{10}) - (7.6 \times 10^9)$

We need to make the powers of 10 the same. We can rewrite $7.6 \times 10^9$ as $0.76 \times 10^{10}$

Now we can subtract:

$(4.39 \times 10^{10}) - (0.76 \times 10^{10}) = (4.39 - 0.76) \times 10^{10} = 3.63 \times 10^{10}$

7. $(1.4 \times 10^6) - (7.63 \times 10^5)$

We need to make the powers of 10 the same. We can rewrite $7.63 \times 10^5$ as $0.763 \times 10^6$

$(1.4 \times 10^6) - (0.763 \times 10^6) = (1.4-0.763) \times 10^6 = 0.637 \times 10^6$

8. $(9.37 \times 10^8) + (9.41 \times 10^7)$

We need to make the powers of 10 the same. We can rewrite $9.41 \times 10^7$ as $0.941 \times 10^8$

$(9.37 \times 10^8) + (0.941 \times 10^8) = (9.37 + 0.941) \times 10^8 = 10.311 \times 10^8 = 1.0311 \times 10^9$

9. $(7.49 \times 10^{-4}) + (8 \times 10^{-5})$

We need to make the powers of 10 the same. We can rewrite $8 \times 10^{-5}$ as $0.8 \times 10^{-4}$.

$(7.49 \times 10^{-4}) + (0.8 \times 10^{-4}) = (7.49 + 0.8) \times 10^{-4} = 8.29 \times 10^{-4}$

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0. $(6.05 \times 10^{-10}) - (5 \times 10^{-11})$

We need to make the powers of 10 the same. We can rewrite $5 \times 10^{-11}$ as $0.5 \times 10^{-10}$.

$(6.05 \times 10^{-10}) - (0.5 \times 10^{-10}) = (6.05 - 0.5) \times 10^{-10} = 5.55 \times 10^{-10}$

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1. $(1.8 \times 10^{15}) - (8.75 \times 10^{14})$

We need to make the powers of 10 the same. We can rewrite $8.75 \times 10^{14}$ as $0.875 \times 10^{15}$.

$(1.8 \times 10^{15}) - (0.875 \times 10^{15}) = (1.8 - 0.875) \times 10^{15} = 0.925 \times 10^{15}$

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2. $(9.9 \times 10^{-7}) + (9.8 \times 10^{-6})$

We need to make the powers of 10 the same. We can rewrite $9.9 \times 10^{-7}$ as $0.99 \times 10^{-6}$.

$(0.99 \times 10^{-6}) + (9.8 \times 10^{-6}) = (0.99 + 9.8) \times 10^{-6} = 10.79 \times 10^{-6} = 1.079 \times 10^{-5}$

3. Final Answer

1. $8.55 \times 10^4$

2. $1.575 \times 10^8$

3. $3.6 \times 10^{-5}$

4. $0.495 \times 10^9$

5. $1.0415 \times 10^{14}$

6. $3.63 \times 10^{10}$

7. $0.637 \times 10^6$

8. $1.0311 \times 10^9$

9. $8.29 \times 10^{-4}$

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0. $5.55 \times 10^{-10}$

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1. $0.925 \times 10^{15}$

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2. $1.079 \times 10^{-5}$