1990 AMC 8 Problem 1

Attempt Problem 1 of the 1990 AMC 8 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1990 AMC 8 solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

1.

What is the smallest sum of two 33-digit numbers that can be obtained by placing each of the six digits 4,4, 5,5, 6,6, 7,7, 8,8, 99 into one of the six boxes of a sum of two 33-digit numbers?
947947
10371037
10471047
10561056
12451245
Answer: C
Concepts:place valueoptimization
Small hint:
A digit in the hundreds place counts 100100 times, so put the smallest digits there
Big hint:
Hundreds digits should be 44 and 55, tens digits 66 and 77, units digits 88 and 99
Solution:
To make the sum small, the two smallest digits go in the hundreds places, the next two in the tens places, and the two largest in the units places.
One such arrangement is 468+579=1047468 + 579 = 1047, and every arrangement of this type gives the same sum.
Thus, the correct answer is C .
LIVE by Po-Shen Loh
Programs

LIVE Classes

Self-Paced Classes

Stars

Scholarship

About Us

Who Is Po-Shen Loh?

Email Contact

Newsletter

Jobs

Become a Star

For a more Thought Full world.

© 2026 Expii, Inc.