Fractions and decimals

Fill in the missing numerator: $\dfrac{3}{4} = \dfrac{?}{20}$.

On a number line, which point is further from $0$: $\tfrac18$ or $\tfrac15$?

Sipho says $\tfrac12 + \tfrac13 = \tfrac25$. What is the best reply?

Work out $\dfrac{2}{3} + \dfrac{1}{4}$. Write the answer in twelfths: $\dfrac{?}{12}$.

Kiri ran $0.25$ km and Ana ran $0.3$ km. Who ran further?

Write $0.125$ as a fraction with denominator $1000$: $0.125 = \dfrac{?}{1000}$.

What is $4 \times \tfrac23$?

Which of these fractions have a decimal that stops? (Choose all that apply.)

In Lean, Gideon says that the fractions $\tfrac{a}{b}$ and $\tfrac{c}{d}$ are equivalent when a * d = c * b. Which statement does Lean need to check to show that $\tfrac24$ is equivalent to $\tfrac12$?

Write add_fractions(a, b, c, d) that returns the sum $\tfrac{a}{b} + \tfrac{c}{d}$ as a pair (numerator, denominator) in simplest form. The starter uses the wrong rule from the lesson, so the tests fail. Use $\tfrac{a \times d + c \times b}{b \times d}$, then divide top and bottom by their greatest common factor, math.gcd.