Peter has 10 balls numbered from 0 to 9. He gives John 3 balls, George 4 balls and Ann 3 balls. Peter then asks each friend to multiply the numbers on their balls. John obtains 0, Georgr obtains 72 and Ann obtains 90. What is the sum of the numbers on John’s balls?
Sylvia draws figures using line segments 1 cm long. At the end of each segment she always turns left or right to draw the next segment. She uses the symbols ♡ and ♠ for turning left and right, but not necessarily in that order. Which figure below results from the sequence ♡ ♠ ♠ ♠ ♡ ♡, starting at point A?
A dragon has 5 heads. Every time a knight cuts off one head, 5 new heads grow in its place. How many heads does the dragon have after the knight has cut off a head 6 times?
The hanging mobile shown below is balanced. The total mass of its shapes is 144 grams. The rods have negligible mass.
1. Compare the combined mass of , , with the combined mass of , , , . Find both totals.
2. Compare the mass of with the combined mass of , , . What is the total mass of , , ?
3. Compare the mass of with the combined mass of , . What is the total mass of and ?
4. Compare the masses of and . What is the mass of ?
A rectangular sheet of paper measures 192 × 84 mm. Alex makes one straight cut to obtain a square. He then repeats this process on the remaining pieces that are not squares. What is the side length, in millimetres, of the smallest square he obtains?
The average age of a grandfather, a grandmother and their 5 grandchildren is 24. The average age of the 5 grandchildren is 11. The grandfather is 3 years older than the grandmother. How old is the grandfather now?
To decorate the dining tables at a Christmas party, 15 candleholders are used. Six of them hold 5 candles each, and the remaining holders hold 3 candles each.
How many candles are needed to fill all these candleholders?
The date 9 March 2012 can be written as 09.03.12. Notice that the day number plus the month number equals the two-digit year number: 9 + 3 = 12. How many dates in 2012 have this property?
Mary has 5 pencils. Michael has fewer pencils than Mary. Their older sister has as many pencils as Mary and Michael have together. Which of the following could be the total number of pencils the three siblings have?
This time, Dad draws a different figure on the paper and repeats the same procedure as above. He places the paper face down and flips it to the right, as shown.
If Dad flips the paper upwards instead, which figure will Anna see?
Source-context note: the preceding story introduces Anna and her father, who draws on paper, places it face down and flips it to reveal the picture.
Helga the chicken lives with her father, mother and one brother, as well as one dog, two cats, two parrots and four fish. How many legs do all the animals living in Helga’s home have altogether?
Four friends, Ngạn, Dũng, Hà Lan and Trà Long, go to the cinema and sit in four consecutive seats. Ngạn does not want to sit next to Dũng. How many seating arrangements are possible?
, 
, 
with the combined mass of 
, 
, 
, 
. Find both totals.
