Efectuati:
[21-(17x6-816:8)x3]:7=


Răspuns :

[21-(17x6-816:8)x3]:7=
[21-(102-102)x3]:7=
(21-0x3):7=
(21-0):7=
21:7=
3
[ 21 - ( 17 × 6 - 816 : 8 ) × 3 ] : 7 =

[ 21 - ( 102 - 102 ) × 3 ] : 7 =

( 21 - 0 × 3 ) : 7 =

( 21 - 0 ) : 7 =

21 : 7 = 3

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