Level 3
Jim has 5 green marbles and some red marbles. Then his sister gave him 2 more red marbles and he has a total of 10 marbles. How many red marbles did he have at first?
Level 3
I am a 4-digit number. The digit in the hundreds place is 6 less than the ones place. The digit in the tens place is 3 more than the thousands place. Which of the following numbers am I?
5288, 2523, 5427
Level 3
Three clowns, Bobo, Toto and Dodo each has 10 balloons. After giving away some of their balloons, Bobo has 5 balloons left, Toto has 3 more balloons than Dodo while Dodo has 2 fewer balloons than Bobo. Find
Level 3
Some adults were at a concert. After 664 women and 2755 men left the concert hall, there were 521 adults left. How many adults were there at the concert hall at first?