AMO 2016 Grade 2

What is the value of $10-9+8-7+6-5+4-3+2-1$?

The right figure is made by placing cubes on top of each other with no gaps. Not all cubes are visible. How many cubes does the figure contain?

Richard chooses any number from 1 to 10. He then adds 34 to it and subtracts 29 from the resulting sum. Afterwards, he adds 55 to the difference. Finally, he subtracts original number from the sum. What is the number he will get after these operations?

Sally is younger than Tristan but older than Umar. Vivian is younger than Winnie but elder than Sally. Who is the youngest among these five people?

On Saturday, Elise bought a furniture from a shop. The furniture will be sent to Elise's house in 30 days. On what day of the week will the furniture reach Elise's house?

The numbers in each row, column, and diagonal of the table below add up to 30. What is the value of $X$?

In the sequence below, each letter represents a number. The sum of any two neighboring numbers is 17. What is the value of the letter $D$?

$A,7,B,C,D$

A jar of 19 chocolates is shared among Leila, Merilyn and Nancy. Merilyn takes more than anyone else. What is the least number of chocolates she could have taken?

Alan has an old grandfather clock. The grandfather clock is moving slower than the normal clock. Every day at 9 am, Alan corrects it from 8:30 am to 9:00 am. One day, Alan went on vacation for 4 days. He left his house at 9:00 am after resetting the clock. When Alan returned after vacation to correct the clock to 9:00 am, what time did the clock show?

In the addition shown, different letters represent different digits. What is the sum of $A$, $B$ and $C$?

It is given that $3\times A=1+2+3+4+5+6$, what is the value of $A$?

A car takes 1 minute, 30 seconds to travel a distance of 1 kilometer. At this rate, how many kilometers will the car travel in 1 hour?

Teacher writes down a four-digit number on the whiteboard. The hundreds digit is the sum of the tens digit and the ones digit. The thousands digit is the sum of the other three. Given that the sum of all four digits is 12, what is the thousands digit of the number?

In each table, the three numbers on the bottom row are used to obtain the number in the top row. If the same pattern is used in each box, what is the value of $?$?

Observe the pattern and find out the number of whole numbers in the sequence below.

$1,2,2,3,3,3,4,4,4,4,5,\ldots,9,10,10,10,10,10,10,10,10,10,10.$