2021 AMC 10B Fall Problem 1

Below is the professionally curated solution for Problem 1 of the 2021 AMC 10B Fall, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2021 AMC 10B Fall solutions, or check the answer key.

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Concepts:place valuepairing and grouping

Difficulty rating: 450

1.

What is the value of 1234+2341+3412+4123?1234 + 2341 + 3412 + 4123?

10,000 10,000

10,010 10,010

10,110 10,110

11,000 11,000

11,110 11,110

Solution:

We can add each individual digit, yielding 11,110.11,110.

We can also get the sum by noticing that each digit has a sum of 10,10, so the sum is equal to 101111=11,110.10\cdot 1111 = 11,110.

Thus, the answer is E .

Problem 1 in Other Years