12 Calculați: a 1-9 +19|+|-2| WHOW b -12|+|-14:2|+|-3|= c |-20|:|-2|+|-3||+61 = d -48|:|+16|+|-84| |-7| =

12.
a. |-9|+|9|+|-2|=9+9+2=20
b. |-12|+|-14:2|+|-3|=12+|-7|+3=12+7+3=22
13.
a. |-1|+|-2|+|-3|+...+|-50|=1+2+3+...+50=50×(50+1)/2=25×51=1275
b. |-3|+|-6|+|-9|+...+|-90|=3+6+9+...+90=3(1+2+3+...+10)=3(10×11/2)=3×5×11=165
Răspuns:
12 Calculați
a)
|-9|+|9|+|-2|
9+9+2
20
b)
|-12|+|-14:2|+|-3|
12+|-7|+3
12+7+3
22
c)
|-20|:|-2|+|-3|×|6|
20:2+3×6
10+18
28
d)
|-48|+|16|+|-84|×|-7|
48:16+84×7
3+588
591
la 13 nu stiu