KA-0061●○○3 points, difficulty 1 of 33 ptLevel 3–4not yet calibratedEach shape stands for a whole number. A triangle plus a triangle plus a triangle is 12, and a triangle plus a square is 9. What is the square?NUM-14Operation puzzles and cryptarithmsalso LOG-08
KA-0062●●○4 points, difficulty 2 of 34 ptLevel 5–6not yet calibrated24 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-0063●●○4 points, difficulty 2 of 34 ptLevel 3–4not yet calibratedWhich of these numbers can be divided exactly by both 4 and 9?NUM-04Divisibility rules: 2, 3, 4, 5, 9, 10also NUM-01
KA-0064●○○3 points, difficulty 1 of 33 ptLevel 5–6not yet calibratedThree quarters of a class of 28 travelled by bus. How many did not travel by bus?NUM-09Fractions of a quantityalso CNT-09
KA-0065●●○4 points, difficulty 2 of 34 ptLevel 5–6not yet calibratedA 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 34 ptLevel 5–6not yet calibratedThe 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-0067●○○3 points, difficulty 1 of 33 ptLevel 3–4has a figurenot yet calibratedA cafe offers 3 main courses and 2 puddings. How many different two-course meals can be ordered?CNT-02Tree diagramsalso CNT-03
KA-0068●●○4 points, difficulty 2 of 34 ptLevel 3–4not yet calibratedA coin is tossed three times. In how many of the possible outcomes are there exactly two heads?CNT-02Tree diagramsalso CNT-01, CNT-04
KA-0069●●○4 points, difficulty 2 of 34 ptLevel 5–6not yet calibratedIn a class of 30, 18 play football and 14 play chess. 6 play both. How many play neither?CNT-10Inclusion–exclusion with two setsalso CNT-09
KA-0070●●●5 points, difficulty 3 of 35 ptLevel 5–6not yet calibratedFive children sit in a row. Two of them are twins who insist on sitting next to each other. In how many orders can the five sit?CNT-11Counting with restrictionsalso CNT-05
KA-0071●●●5 points, difficulty 3 of 35 ptLevel 5–6not yet calibratedFive beads of five different colours are threaded on a circular bracelet. Two bracelets count as the same if one can be turned or flipped into the other. How many different bracelets are there?CNT-16Overcount, then correctalso CNT-15, CNT-05
KA-0072●○○3 points, difficulty 1 of 33 ptLevel 3–4not yet calibratedHow many different two-digit numbers can be written using only the digits 1, 2 and 3, if a digit may be used twice?CNT-01Systematic listingalso CNT-03