Solve 1*2+2*3+3*4+4*5+5*6+6*7+7*8+8*9+9*10

$$1 \times 2+2 \times 3+3 \times 4+4 \times 5+5 \times 6+6 \times 7+7 \times 8+8 \times 9+9 \times 10$$

Evaluate

$$330$$

Solution Steps

Multiply 1 and 2 to get 2. Multiply 2 and 3 to get 6. Multiply 3 and 4 to get 12. Multiply 4 and 5 to get 20. Multiply 5 and 6 to get 30. Multiply 6 and 7 to get 42. Multiply 7 and 8 to get 56. Multiply 8 and 9 to get 72. Multiply 9 and 10 to get 90.

$$2+6+12+20+30+42+56+72+90$$

Add 2 and 6 to get 8.

$$8+12+20+30+42+56+72+90$$

Add 8 and 12 to get 20.

$$20+20+30+42+56+72+90$$

Add 20 and 20 to get 40.

$$40+30+42+56+72+90$$

Add 40 and 30 to get 70.

$$70+42+56+72+90$$

Add 70 and 42 to get 112.

$$112+56+72+90$$

Add 112 and 56 to get 168.

$$168+72+90$$

Add 168 and 72 to get 240.

$$240+90$$

Add 240 and 90 to get 330.

$$330$$

Factor

$$2\times 3\times 5\times 11$$