Simplify the following expressions:

i) [tex][tex]$1.3 \times 10^5 - 4.9 \times 10^4$[/tex][/tex]

ii) [tex][tex]$3.3 \times 10^{-4} - 5.2 \times 10^{-3}$[/tex][/tex]

iii) [tex][tex]$4.8 \times 10^{-5} - 3.5 \times 10^{-6}$[/tex][/tex]

iv) [tex][tex]$5.4 \times 10^{-3} - 8.6 \times 10^{-5}$[/tex][/tex]



Answer :

Sure, let's solve each of the expressions step-by-step:

### Part i) [tex]\(1.3 \times 10^5 - 4.9 \times 10^4\)[/tex]

1. First, express each term in standard form:
[tex]\[ 1.3 \times 10^5 = 130000 \][/tex]
[tex]\[ 4.9 \times 10^4 = 49000 \][/tex]

2. Subtract the second term from the first:
[tex]\[ 130000 - 49000 = 81000 \][/tex]

So, the result is:
[tex]\[ 81000.0 \][/tex]

### Part ii) [tex]\(3.3 \times 10^{-4} - 5.2 \times 10^{-3}\)[/tex]

1. First, express each term in standard form:
[tex]\[ 3.3 \times 10^{-4} = 0.00033 \][/tex]
[tex]\[ 5.2 \times 10^{-3} = 0.0052 \][/tex]

2. Subtract the second term from the first:
[tex]\[ 0.00033 - 0.0052 = -0.00487 \][/tex]

So, the result is:
[tex]\[ -0.00487 \][/tex]

### Part iii) [tex]\(4.8 \times 10^{-5} - 3.5 \times 10^{-6}\)[/tex]

1. First, express each term in standard form:
[tex]\[ 4.8 \times 10^{-5} = 0.000048 \][/tex]
[tex]\[ 3.5 \times 10^{-6} = 0.0000035 \][/tex]

2. Subtract the second term from the first:
[tex]\[ 0.000048 - 0.0000035 = 0.0000445 \][/tex]

Express the result back in scientific notation:
[tex]\[ 0.0000445 = 4.45 \times 10^{-5} \][/tex]

So, the result is:
[tex]\[ 4.45 \times 10^{-5} \][/tex]

### Part iv) [tex]\(5.4 \times 10^{-3} - 8.6 \times 10^{-5}\)[/tex]

1. First, express each term in standard form:
[tex]\[ 5.4 \times 10^{-3} = 0.0054 \][/tex]
[tex]\[ 8.6 \times 10^{-5} = 0.000086 \][/tex]

2. Subtract the second term from the first:
[tex]\[ 0.0054 - 0.000086 = 0.005314 \][/tex]

So, the result is:
[tex]\[ 0.005314 \][/tex]

### Summary
- Part i) [tex]\(1.3 \times 10^5 - 4.9 \times 10^4 = 81000.0\)[/tex]
- Part ii) [tex]\(3.3 \times 10^{-4} - 5.2 \times 10^{-3} = -0.00487\)[/tex]
- Part iii) [tex]\(4.8 \times 10^{-5} - 3.5 \times 10^{-6} = 4.45 \times 10^{-5}\)[/tex]
- Part iv) [tex]\(5.4 \times 10^{-3} - 8.6 \times 10^{-5} = 0.005314\)[/tex]