Răspunsuri

2014-09-04T11:39:29+03:00
A) 10(1+2+3+....+123)=10(123·124:2)=10·123·62=1230·62=39360
b) 7(1+2+3+......+45)=7(45·46:2)=7·45·23=315·23=7245