X0306 4 2020-11-24 0000007431 ARMSTRONG WORLD INDUSTRIES INC AWI 0001322386 Hershey Mark A C/O ARMSTRONG WORLD INDUSTRIES, INC. 2500 COLUMBIA AVENUE LANCASTER PA 17603 1 SVP, Gen Cnsl, Compliance Common Stock 2020-11-24 4 M 0 200 80.045 A 44687 D Common Stock 2020-11-24 4 M 0 100 80.04 A 44787 D Common Stock 2020-11-24 4 S 0 300 80.043 D 44487 D Stock Options (Right to Buy) 45.32 2020-11-24 4 M 0 200 0 D 2023-02-20 Common Stock 200 200 D Stock Options (Right to Buy) 47.17 2020-11-24 4 M 0 100 0 D 2024-02-25 Common Stock 100 100 D Option exercised and shares sold pursuant to a 10b5-1 Plan. The price reported is a weighted average price. These shares were sold in multiple transactions at per share prices ranging from $80.04 to $80.05. The reporting person undertakes to provide upon request to the SEC staff, the Issuer, or any stockholder of the Issuer, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The stock options were granted on February 20, 2013. Grant has a graded vesting schedule. Date Exercisable will vary for each vesting tranche. All options are currently vested and exercisable. The stock options were granted on February 25, 2014. Grant has a graded vesting schedule. Date Exercisable will vary for each vesting tranche. All options are currently vested and exercisable. /s/ Mark A. Hershey 2020-11-25