Intermath | Workshop Support
Write-up


Title
Missing Number

Problem Statement
Each of the letters in the following expression represents unique numbers. If all the digits 1 through 9 appear exactly once, then find the number represented by each letter

:
 
  a 4 b
+ 2 c 5
__________
  d 1 e

 


Problem setup

Each letter represents a unique number

The digits 1-9 appear once

Find the numbers represented by each letter

 

Plans to Solve/Investigate the Problem

Discussed  initial plans with classmates who arrived at answer immediately through knowledge of place values, base 10, borrowing & trading and regrouping

 

Investigation/Exploration of the Problem

 
  a 4 b
+ 2 c 5
__________
  d 1 e
Numbers were inserted via trail & error

the following numbers were determined to be correct

  6 4 3
+ 2 7 5
__________
  9 1 8
1,2,3,4,5,6,7,8,9,
 

a=6

b=3

c=7

d=9

e=8


 

 

Extensions of the Problem

Excel spreadsheet was used to calculate answer by inserting algorithm