Skip to main content

Atlas
Problems
Diagnostic
Mock
Papers
About

The whole Atlas

Number & Arithmetic15
Counting18
Geometry & Visualization18
Logic & Deduction11
Patterns & Sequences7
Modeling & Word Problems10
Contest Craft12

Loading…

About
Sign in
Worksheets
Privacy
Terms
License
Contact
GitHub

Code is MIT. Problems, skills, and explanations are CC BY-NC-SA 4.0. Practice never requires an account and nothing here is paywalled.

Independent project. Not affiliated with or endorsed by Math Kangaroo in USA, NFP.

Home
Atlas
Problems
Papers

Browse the problems

177 problems, every one written from scratch, every wrong answer carrying the mistake that produces it. 708 explanations in all.

Level

1–2
3–4
5–6
7–8
9–10
11–12

Point value

3 pt
4 pt
5 pt

Strand

NUMNumber & Arithmetic
CNTCounting
GEOGeometry & Visualization
LOGLogic & Deduction
PATPatterns & Sequences
MODModeling & Word Problems
CFTContest Craft

Sort

Id
Hardest first
Newest

8 problemsClear all filters

KA-0024
4 points, difficulty 2 of 3Level 5–6not yet calibrated
Red and blue counters are in the ratio 3 to 5. There are 40 counters altogether. How many are red?
NUM-11Ratio as parts of a wholealso NUM-09
KA-0033
4 points, difficulty 2 of 3Level 5–6not yet calibrated
The mean of five numbers is 12. One of the numbers is removed and the mean of the remaining four is 11. What number was removed?
NUM-15Means, and working backwards from a meanalso LOG-08
KA-0053
4 points, difficulty 2 of 3Level 5–6not yet calibrated
What is the remainder when 2 to the power 30 is divided by 7?
NUM-06Remainders and modular cyclesalso PAT-03, NUM-07
KA-0058
4 points, difficulty 2 of 3Level 5–6not yet calibrated
What is 2 + 4 + 6 + ... + 100?
NUM-08Clever regrouping (pair to round numbers)also PAT-02
KA-0062
4 points, difficulty 2 of 3Level 5–6not yet calibrated
24 pencils and 36 erasers are shared into identical gift bags, using every item. What is the largest number of bags possible?
NUM-05Factors, multiples, LCM and GCD by listingalso NUM-04
KA-0065
4 points, difficulty 2 of 3Level 5–6not yet calibrated
A price goes up by 20%, then down by 20%. Compared with the original price, the final price is:
NUM-10Percentages and simple discountsalso NUM-09
KA-0066
4 points, difficulty 2 of 3Level 5–6not yet calibrated
The mean of four numbers is 9. Three of them are 5, 8 and 12. What is the fourth?
NUM-15Means, and working backwards from a meanalso LOG-08
KA-0149
4 points, difficulty 2 of 3Level 5–6not yet calibrated
What is the units digit of 3 multiplied by itself 100 times, that is 3 to the power 100?
NUM-07Last-digit behavior of products and powersalso NUM-06, PAT-03

Browse the problems — Kangaroo Atlas