Ответ:
1) 15 + 1/5 = 75/5 + 1/5 = 76/5 = 15 1/5.
2) 3/8 − 1/9 = 27/72 − 8/72 = 19/72.
3) 2 1/20 − 6 9/40 = 41/20 − 249/40 = 82/40 − 249/40 = −167/40 = −4 7/40.
1) 15 + 1/5 = 75/5 + 1/5 = 76/5 = 15 1/5.
2) 3/8 − 1/9 = 27/72 − 8/72 = 19/72.
3) 2 1/20 − 6 9/40 = 41/20 − 249/40 = 82/40 − 249/40 = −167/40 = −4 7/40.