standard_description: Apply geometric methods to solve design problems (e.g., designing an object or structure to satisfy physical constraints or minimize cost; working with typographic grid systems based on ratios).
problem_activity: Solve.
a.
$${{7\over8}-{4\over8}}$$
b.
$${{5\over10}+{3\over10}}$$
c.
$${1-{2\over5}}$$


aligns: no