Adding a Fifth Row

Ten Pins


The arrangement of the pins for Ten Pins is at right. Say that another row of pins were added. How many pins are in that row?

Row 1 has 1 pin.
Row 2 has 2 pins.
Row 3 has 3 pins.
Row 4 has 4 pins.
Row 5 has pins.

Click the image to see the added row.


There are 10 pins total in the first four rows. Row five has 5 pins. How many pins are there in five rows?

10 + Pins in Row 5 =