NOTE (A)  ★ You can add numbers in any order. Answer remains the same. 21 +78 = 78 + 21 ★ Zero added to any number gives the same number as the sum. 94 + 0 = 94 ★ One added to any number gives its successor as the sum. 94 + 1 = 95 (B)  Zero subtracted from any number g…