Alteryx-Core Data Preparation Practice Question
Exhibit
Error: Formula (12): Parse Error: The formula "[Total] + [Tax]" is invalid. The field 'Total' is a String and cannot be added to a numeric field.
Refer to the exhibit. Which tool should be placed before the Formula tool to resolve this error?
⚠ Common exam trap
Candidates frequently try to use the Formula tool to cast data types using 'ToNumber()' inside the calculation. While possible, the Select tool is the standard, more efficient way to handle type changes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A Select tool to change the field type of 'Total' to a numeric type.
The error indicates a data type mismatch between a string and a numeric field. To perform arithmetic, both fields must be numeric. The Select tool is the standard tool to fix this by explicitly changing the 'Total' field type from String to Double or Int. Fixing this is vital because Alteryx is strictly typed; arithmetic operators will always fail if applied to non-numeric string data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A Formula tool with the ToNumber() function.
Why it's wrong here
While ToNumber can fix the issue within the Formula tool, adding a Select tool is generally preferred for workflow readability and metadata management. Using a Select tool keeps the logic clean and ensures the type change is explicitly visible in the workflow's schema documentation.
- ✓
A Select tool to change the field type of 'Total' to a numeric type.
Why this is correct
The Select tool is the standard interface for correcting metadata issues before they reach calculation tools. By changing the 'Total' field to Double or Int, the subsequent Formula tool can successfully perform the addition without generating a parse error, ensuring smooth execution.
- ✗
A Filter tool to exclude the 'Total' field.
Why it's wrong here
Filtering out the field does not solve the underlying requirement of performing the calculation. It merely removes the data from the stream, which fails the business objective of the calculation. The goal is to correct the data type, not to eliminate the data itself.
- ✗
A Multi-Row Formula tool.
Why it's wrong here
The Multi-Row Formula tool is designed for calculations that involve previous or subsequent rows, not for fixing data type incompatibilities. It would face the same parse error as the standard Formula tool because the underlying data type issue remains unaddressed in the workflow stream.
Visual reference
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Alteryx exam blueprint
This Alteryx-Core practice question is part of Courseiva's free Alteryx certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the Alteryx-Core exam.