Tính các tổng sau một cách hợp lí

Bài 1. Tính các tổng sau một cách hợp lí

a) 917 – (417 – 65)

c) 54 + (–37 + 10 – 54 + 67)

e) (351 – 875) – (125 – 149)

g) 5 – 197 – 2015 – 2015

i) –45789 – 357 – 45789 + 57

l) –7105 – (155 – 7105) + 355

n) –5 + –37 – 45 + 151 – –37 + 151

p) –81 – 132 – 547 + 181 – 132 – 53

r) 254 – 49 – 75 + 254 – 175 + 549

t) (–2) + 7 + (–12) + 17 +…+ (–52) + 57

b) 31 – [26 – (2017 + 35)] d) (326 – 43) + (174 – 57)

f) (35 – 815) – (795 – 65) h) 2004 – 15 + 54 – 2004 – 54

k) 1259 – 1409 – 12 + 1259 + 1409

m) 2750 – 1229 + 2750 – [–438 – 29 – 438]

o) 53 – 145 – 359 – 53 + 145 – 259

q) 50 – 2016 + 50 – 118 + 2016 – 18

s) 173 – 536 + 173 – [29 – 29 + 526]

u) (–30) + (–29) + … + 48 + 49 + 50

v) –[–171 + 171 + 223] – [172 – 105 + 172] + 223