Greatest Sum from Digits

Free interactive math game: Greatest Sum from Digits — Arrange to maximize. Part of the Addition & Subtraction category on MathKite.

Example problems

Taken from the generator that powers this exercise. A fresh set appears every time the page is opened, and the printable worksheet holds ten of them.

Using the digits 9, 1, 5, 3 exactly once each, make two 2-digit numbers whose sum is as large as possible. What is this greatest sum?
Using the digits 1, 2, 4, 9 exactly once each, make two 2-digit numbers whose sum is as large as possible. What is this greatest sum?
Using the digits 1, 4, 8, 7 exactly once each, make two 2-digit numbers whose sum is as large as possible. What is this greatest sum?
Using the digits 2, 7, 3, 1 exactly once each, make two 2-digit numbers whose sum is as large as possible. What is this greatest sum?

Arranging digits to build the largest possible total — an exercise in place value rather than addition.

How to solve it

A digit in the tens place is worth ten times what it is worth in the ones place, so give the two largest digits the tens positions.

Worked example

With 8, 5, 7 and 2 put 8 and 7 in the tens to make 82 and 75, which total 157.

Common mistake

Building the two largest numbers instead of the largest sum. What matters is which digits land in the tens column, not how the pairs are formed.