Calculate: $$1+2+3+4+5+6+7+8+9+10+9+8+7+6+5+4=$$． 
Overseas Competition->Knowledge Point->Calculation Modules->Sequences and Number Tables->Patterns in Number Sequences->Pyramid Sequences
$$1+2+3+4+5+6+7+8+9+10+9+8+7+6+5+4$$  $$=1+2+3+4+5+6+7+8+9+10+9+8+7+6+5+4+3+2+1-3-2-1$$  $$=10\times 10-6$$  $$=100-6$$  $$=94$$． 