Răspuns :
Răspuns:
d) 1+3+5...+21=21×(21+1):2
=21×22:2
= 21×11
= 231
e) 1+4+7+10......37=37×(37+1):2
=37×38:2
=37×19
=703
f)5+10+15....+100=100×(101+1):2
=100×102:2
=100×5,4
= 5400
Răspuns:
d) 1+3+5...+21=21×(21+1):2
=21×22:2
= 21×11
= 231
e) 1+4+7+10......37=37×(37+1):2
=37×38:2
=37×19
=703
f)5+10+15....+100=100×(101+1):2
=100×102:2
=100×5,4
= 5400