668.

1) (437*8 - (1961+6583) : 534) : 145=

2) 1000 - ((715*20+1348) : 163+879) =

3) 484 + (18 * (345+4465:235) - 3400) : 197

1)

1.1961+6583=8544

2.8544:534=16

3.437*8=3496

4.3496-16=3480

5.3480:145=24

2)

1.715*20=14300

2.14300+1348=15648

3.15648:163=96

4.96+879=975

5.1000-976=25

3)

1.4465:235=19

2.345+19=364

3.18*364=6552

4.6552-3400=3152

5.3152:197=16

6.484+16=500