easy
3-1
2
23-9
14
342-127
215
If you have 5 apples and you take away 3, how many apples do you have?
You took 3 apples, so you have 3.
In a school of 500 students,
300 study Math
250 study Physics
200 study Chemistry
150 study Math & Physics
120 study Math & Chemistry
100 study Physics & Chemistry
60 study all three
Question: How many study only Math?
300 − 150 − 120 + 60 = 90
7-6
1
34-16
18
666-347
319
A farmer has 17 sheep. All but 9 run away. How many sheep are left?
All but 9” means 9 remain.
A library has 800 books:
420 are in English
350 in Spanish
300 in French
180 in English & Spanish
120 in English & French
100 in Spanish & French
50 in all three
Question: How many books are only in English?
420 − 180 − 120 + 50 = 170
5-4
1
64-37
27
999-657
342
Which weighs more: 1 kg of feathers or 1 kg of iron?
They weigh the same.
luck
500
6-2
4
57-23
34
566-321
245
if a plane crashes exactly on the border between two countries, where are the survivors buried?
They aren’t buried.Survivors are alive.
In a company of 600 workers:
340 know Excel
300 know Python
260 know SQL
150 know Excel & Python
130 know Excel & SQL
120 know Python & SQL
70 know all three
Question: How many workers know exactly two skills?
(150 + 130 + 120) − 3×70 = 190
12-5
7
98-58
40
In a class of 200 students:
Math = 120
Physics = 110
Computer Science = 90
Math & Physics = 70
Math & CS = 50
Physics & CS = 40
Everyone studies at least one subject.
200 = 120 + 110 + 90 − 70 − 50 − 40 + x
200 = 160 + x
x = 40
✅ Answer: 40
You enter a dark room with a match. Inside there is a candle, a lamp, and a fireplace. What do you light first?
The match. You must light the match before anything else.
At a tech event with 900 visitors:
500 use Android
450 use iPhone
300 use Windows laptops
220 use Android & iPhone
200 use Android & Windows
180 use iPhone & Windows
120 use all three
Question: How many use only Android?
500 − 220 − 200 + 120 = 200