1) 742 + 39 + 58 = (742 + 58) + 39 = 800 + 39 = 839
2) 973 + 115 – 273 = (973 – 273) + 115 = 700 + 115 = 815
3) 832 – 15 – 32 = (832 – 32) – 15 = 800 – 15 = 785
4) 2 • 115 • 50 = 115 • (2 • 50) = 115 • 100 = 11 500
5) 29 • 19 + 71 • 19 = (29 + 71) • 19 = 100 • 19 = 1 900
6) 192 • 37 – 92 • 37 = (192 – 92) • 37 = 100 • 37 = 3 700