## GST Calculation

**Given:**
- Tax invoice total (GST-inclusive): **$1,100**
- GST rate: **10%**

### (a) GST Amount

To extract the GST from a GST-inclusive amount, divide by 11:

$$
\text{GST} = \frac{\$1{,}100}{11} = \$100
$$

**GST amount included in the invoice: $100**

### (b) GST-Exclusive Price

Subtract the GST from the invoice total:

$$
\$1{,}100 - \$100 = \$1{,}000
$$

**GST-exclusive price: $1,000**