Pls explain how to get answer without excel

Question 3 0 / 1 point There is a Government of Canada zero bond outstanding. It has a face value of $500,000. It has 20 years to maturity. Currently the yield to maturity on the bond is 6.5%. Suppose that tomorrow the yield to maturity decreases by 0.4%. The term structure (yield curve) is flat. What will be the percentage increase in the value of the bond? Your answer should be shown as a percentage and it should be accurate to two decimal places. Answer: x (7.82) Question 4 0 / 1 point You just purchased a bond. You paid $805 for the bond. The bond has 38 years to maturity and a face value of $1,000. The coupon rate is 5.5% and the coupons are paid annually. What is the bond's current yield? Your answer should be shown as a percentage and it should be accurate to two decimal places. Answer: x (6.83) Question 5 0 / 1 point You are going to purchase a Government of Ontario bond. The bond has a face value of $900,000. The bond has 22 years to maturity. The bond has a coupon rate of 5.7%. Coupons are paid semi-annually. The yield to maturity on the bond is 5.4%. How much will you have to pay for the bond? Your answer should be accurate to two decimal places. Answer: x (934,516.45)