1. **Work out 487.52 - 86.74 - 52.81** Start with the first subtraction: $$487.52 - 86.74 = 400.78$$ Then subtract 52.81: $$400.78 - 52.81 = 347.97$$ So, the answer is **347.97**. 2. **How many miles did the pilot fly in total?** Add all the distances: $$5642 + 4081 + 10506 + 5579 = 25708$$ The pilot flew a total of **25708 miles**. 3. **Use the digits 3, 5, 7, 8 to fill in the missing digits on the number line:** Given numbers: - First number: □.7□ - Second number: □.□0 The numbers must lie between 7 and 9. Try possible combinations: - First number: 7.38 (using digits 3 and 8) - Second number: 8.50 (using digits 5 and 0) Both numbers are between 7 and 9 and use all digits 3,5,7,8 exactly once. So, the two completed numbers are **7.38** and **8.50**. 4. **Find digits A, B, and C in the addition problem:** Given: \begin{align*} 15.73 \\ + 32.4A \\ + C.16 \\ \hline 48.B4 \end{align*} Add the numbers column-wise from right to left: - Hundredths place: 3 + A + 6 = 4 (units digit) + carry Since 3 + A + 6 = 9 + A, to end with 4, 9 + A must be 14, so A = 5 and carry 1. - Tenths place: 7 + 4 + 1 (carry) + 1 (from C.16) = B + 10 * carry 7 + 4 + 1 + 1 = 13, so B = 3 and carry 1. - Units place: 5 + 2 + C + 1 (carry) = 8 + 10 * carry 5 + 2 + C + 1 = 8 + 10 * carry 8 + C = 8 + 10 * carry So, C = 0 and carry 0. Therefore, A = 5, B = 3, C = 0. 5. **Add 387 to 115, then subtract 141:** First add: $$387 + 115 = 502$$ Then subtract: $$502 - 141 = 361$$ The final answer is **361**.