Question

Afla numarul necunoscut:
a + 989 = 2 007
2 196 + b = 4 015
c - 1 917 = 3 595
10000 - d = 3 480

a + (980 + 796) = 4 000
(2 901 - 6 156) = 5 435
c - (10 000 - 8 903) - 3 679
( 9 980 - 7 675) - d = 980

Answer 1

~a+989=2007
=>a=2007-989
=>a=1018

~2196+b=4015
=>b=4015-2196
=>b=1819

~c-1917=3595
=>c=3595+1917
=>c=5512

~10000-d=3480
=>d=10000-3480
=>d=6520

~a+(980+796)=4000
a+1776=4000
=>a=4000-1776
=>a=2225