1) (594 + 6) + (847 + 153) = 600 + 1000 = 1600

2) (2 * 5) * (5 * 20) * (9 * 8) = 10 * 100 * 72 = 72000

3) 72 * (34 + 66) = 72 * 100 = 7200

4) 614 + (978 - 978) = 614

5) (832 - 732) - 15 = 100 - 15 = 85

6) 715 * (341 - 241) = 715 * 100 = 71500