Geometry Puzzle – Critical Thinking 20
To solve this kind of challenge, sometimes it just needs logical steps and other times it involves lateral out-of-the-box thinking!
Challenge:
In how many 3-digit numbers the sum of all digits is 7?
The Absolute Best Book to Challenge Your Smart Student!
$11.99
Satisfied 123 Students
The correct answer is 28.
First, let’s find all three digits that add up to 7.
700, 610, 511, 520, 430, 421, 322, 133
For 7, 0 and 0, we can write only one three digit number which is 700.
For 6, 1 and 0, we can find 106, 160, 601, 610,
For 5, 1, and 1: 115, 151, 511
For 5, 2, and 0: 205, 250, 502, 520
For 4, 3, and 0: 304, 340, 403, 430
For 4, 2, and 1: 124, 142, 214, 241, 412, 421
For 3, 2, and 2: 223, 232, 322
For 1, 3, and 3: 133, 313, 331
There are 28 three digits numbers that the sum of their digits is 7.
The Absolute Best Books to Ace Algebra
$14.99
Satisfied 1 Students
$14.99
Satisfied 92 Students
$15.99
Satisfied 125 Students
Related to This Article
More math articles
- 8th Grade SBAC Math FREE Sample Practice Questions
- The Ultimate TASC Math Course (+FREE Worksheets & Tests)
- How to Use Strip Models to Subtract Fractions with Like Denominators
- Embarking on an Adventure: How to Solve Word Problems Involving Percents of Numbers and Percent Equations
- An In-depth Exploration of How to Find the Codomain
- Top 10 Praxis Core Math Prep Books (Our 2023 Favorite Picks)
- 6th Grade ACT Aspire Math FREE Sample Practice Questions
- How to Find Vague Limits by Change of Function’s Value
- How to Categorize Rational Numbers
- How to Graph Solutions to One-step and Two-step Linear Inequalities
What people say about "Geometry Puzzle – Critical Thinking 20 - Effortless Math: We Help Students Learn to LOVE Mathematics"?
No one replied yet.