By the Numbers

By the numbers is a recurring immunity challenge in Survivor

Rules
The tribes a lined up on a very narrow balance beam. One tribe member at a time, they must move across the beam and around the other tribe members. The person crossing can only touch one member at a time. If they touch two people at once or fall into the water, they must start all over. Once a member reaches the platform, the next person goes.The tribe who gets all their members across first wins.

Usage
The challenge was first used in Survivor: Vanuatu in Burly Girls, Bowheads, Young Studs, and the Old Bunch for reward. The Yasur tribe was easily able to win the challenge for reward in the form of Blankets and Pillows, while the Lopevi tribe struggle to get across.

In Survivor: Fiji in "Let's Just Call Jeff on the Jeff Phone". Moto sat out Gary Stritesky and Cassandra Franklin for reward. Moto and Ravu  started the challenge on even ground. Moto developed a strategy with the member kneel down allowing them to cross with relative ease. This would give Moto to win easily and earn Fish, Rice, Spices, and a king-sized bed with sheets, pillows and blankets.

In Survivor: One World in Total Dysfunction for Immunity. While the Manono made decent progress The Salani tribe had communications problems early on, made worst by Kat unnecessarily jumping into the water. By the time Monica was able to come up with a plan and got a woman across, The Manono had seven members across and won immunity.

Trivia

 * This challenge is mostly use in Battle of the Sexes format seasons