a) 79. 101

= 79 . (100 + 1)

= 79. 100 + 79

= 7 900 + 79

= 7 979

b) (1 999 + 2 016) - 1 999

= ( 1 999 - 1 999) + 2 016

= 0 + 2 016

= 2 016

c) 81 + 250 + 19

= (81 + 19) + 250

= 100 + 250

= 350

d) 165 + 79 + 135

= (165 + 135) + 79

= 300 + 79

= 379

e) 35 . 45 + 35 . 55

= 35 . (45 + 55)

= 35. 100

= 3 500

f) 5. 125 . 2. 8

= (5 . 2) . (125 . 8)

= 10 . 1 000

= 10 000