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!
[include_netrun_products_block from-products="product/ged-math-test-prep-in-30-days-complete-study-guide-and-test-tutor-for-ged-mathematics-the-ultimate-book-for-beginners-and-pros-two-practice-tests/" product-list-class="bundle-products float-left" product-item-class="float-left" product-item-image-container-class="p-0 float-left" product-item-image-container-size="col-2" product-item-image-container-custom-style="" product-item-container-size="" product-item-add-to-cart-class="btn-accent btn-purchase-ajax" product-item-button-custom-url="{url}/?ajax-add-to-cart={id}" product-item-button-custom-url-if-not-salable="{productUrl} product-item-container-class="" product-item-element-order="image,title,purchase,price" product-item-title-size="" product-item-title-wrapper-size="col-10" product-item-title-tag="h3" product-item-title-class="mt-0" product-item-title-wrapper-class="float-left pr-0" product-item-price-size="" product-item-purchase-size="" product-item-purchase-wrapper-size="" product-item-price-wrapper-class="pr-0 float-left" product-item-price-wrapper-size="col-10" product-item-read-more-text="" product-item-add-to-cart-text="" product-item-add-to-cart-custom-attribute="title='Purchase this book with single click'" product-item-thumbnail-size="290-380" show-details="false" show-excerpt="false" paginate="false" lazy-load="true"]
Challenge:
In how many 3-digit numbers the sum of all digits is 7?
The Absolute Best Book to Challenge Your Smart Student!
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
Related to This Article
More math articles
- How Smart Bettors Use Math to Beat the Books
- How to Solve Rational Numbers Word Problems
- 5 Best Mini Laptops to Use Anytime, Anywhere
- How to Understand the Key Properties of Trapezoids
- How to Motivate Anyone to Start Learning Algebra and Geometry
- The Ultimate NYSTCE Grades 1-6 Math (222) Course (+FREE Worksheets & Tests)
- How to Apply Comparison, Ratio, and Root Tests
- How to Find Missing Sides and Angles of a Right Triangle? (+FREE Worksheet!)
- How to Modeling Real-World Situations Using Functions
- 4th Grade MCA Math Worksheets: FREE & Printable

















What people say about "Geometry Puzzle – Critical Thinking 20 - Effortless Math: We Help Students Learn to LOVE Mathematics"?
No one replied yet.