1. **State the problem:** Find the gradient (slope) of the straight line passing through points (0,0), (1,1), (2,2), and (3,3). 2. **Formula for gradient:** The gradient $m$ of a straight line passing through two points $(x_1,y_1)$ and $(x_2,y_2)$ is given by: $$m = \frac{y_2 - y_1}{x_2 - x_1}$$ 3. **Apply the formula:** Using points $(0,0)$ and $(1,1)$: $$m = \frac{1 - 0}{1 - 0} = \frac{1}{1}$$ 4. **Simplify:** $$m = 1$$ 5. **Interpretation:** The gradient of the line is 1, meaning the line rises 1 unit vertically for every 1 unit it moves horizontally. This confirms the line has a positive slope of 1.