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!
Original price was: $16.99.$11.99Current price is: $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
Original price was: $29.99.$19.99Current price is: $19.99.
Original price was: $29.99.$14.99Current price is: $14.99.
Original price was: $29.99.$14.99Current price is: $14.99.
Satisfied 1 Students
Original price was: $24.99.$14.99Current price is: $14.99.
Satisfied 92 Students
Original price was: $24.99.$15.99Current price is: $15.99.
Satisfied 125 Students
Related to This Article
More math articles
- Top 10 ACT Math Prep Books (Our 2023 Favorite Picks)
- The Ultimate 7th Grade PEAKS Math Course (+FREE Worksheets)
- Integrals: Complete Explanation of the Applications and Use
- 10 Most Common 6th Grade IAR Math Questions
- 8th Grade PSSA Math FREE Sample Practice Questions
- 8th Grade MEAP Math FREE Sample Practice Questions
- FREE 3rd Grade MAP Math Practice Test
- Derivative of Logarithmic Functions: A Hard Task Made Easy
- Pattern Play: How to Analyzing and Comparing Mathematical Patterns
- PSAT Cаlсulаtоr Pоliсу
What people say about "Geometry Puzzle – Critical Thinking 20 - Effortless Math: We Help Students Learn to LOVE Mathematics"?
No one replied yet.