Problems
Random
Operations
100
With a full tank, a car can travel 800 km. How far would you travel with two-fifths of the car's tank?
320 km
2/5*800=(2*800)/5=320
100
Move a stick to make equality true
-1+1=0
100
Calculate in only 10 seconds.
10-(5-3x4)
17
200
Calculate three numbers knowing that:
— The first is 20 units smaller than the second.
—The third is equal to the sum of the first two.
— The sum of the three numbers is 120.
20, 40 y 60
200
Can you correct the operation without touching or adding any matches?
200
Factor the number 100000 in 20 seconds
100000=10*10*10*10*10
100000=2*5*2*5*2*5*2*5*2*5
100000=2^5*5^5
300
How can you get 100 with 4 numbers 9?
9/9+99=100
300
Calculate the last equation in 1 minute
11
300
Calculate the generating fraction
(179-17)/90=9/5
400
It takes three painters six days to paint a house. How long would it take if there were two painters?
2/3=6/x
x=(3*6)/2=9
400
Solve the last equation in 90 seconds:
16
400
Calculate in two minutes:
43/42
500
A train leaves Madrid for Barcelona at 8:00. Another train leaves Barcelona for Madrid at 9:00 at double speed. When the two trains cross, which one will be closer to Madrid?
At the same distance since when they cross they are right in the same place, therefore the distance to any place is the same
500
Using 6 pens, build a figure that has 4 triangles in 2 minutes
The solution is a tetrahedron
500
Place the numbers from 1 to 9 without repeating any, each one in a circle, so that the operations are correct. The two circles stuck together represent a two-digit number.
