Can you solve it? Carl Friedrich Gauss, money saving expert

Take the 2021 envelope challenge!

UPDATE: To read the answers click here

Financially well-informed readers may have recently learned about a money-saving trick that uses a formula supposedly devised by Carl Friedrich Gauss, the 19th century maths colossus. The viral 100 envelope challenge is based on an apocryphal story that Gauss, when a young boy, outwitted his teacher by adding the numbers from 1 to 100 almost instantly.

The child genius had realised that if you group the numbers from 1 to 100 in pairs, the sum is equal to (1 + 100) + (2 + 99) + (3 + 98) + ... In other words, 101 + 101 + 101 + ... Since there are 50 pairs of numbers, the sum is 101 x 50 = 5050.