Transcript Fun Arithmetic - Raise Smart Kids

Fun Arithmetic
Created by Inna Shapiro ©2008
Problem 1
Max has ten cards with the digits 0, 1, 2,…9.
He can arrange these cards into different
10-digit numbers.
What is the greatest number that he can get?
Answer
The greatest number should start with
the greatest digit 9. The second digit
will be the greatest of the rest, i.e. 8,
and so on.
The greatest number is 9876543210.
Problem 2
A teacher has four cards with numbers.
The sum of these numbers is equal to 8.
When the teacher shows these cards to Mary
and asks to multiply the numbers, Mary also
gets 8.
What numbers are on the cards? Some
numbers could be equal.
Answer
The numbers are
1, 1, 2, and 4.
Problem 3
Ron has five cards with the digit 1.
How can he arrange them to
compose the number 100 using the
arithmetic operations +, -, *, and / ?
Answer
100=111-11
Problem 4
Monty has five cards with the digit 5.
How can he arrange his cards to get
the number 100 using the arithmetic
operations +, -, *, and / ?
Answers
100=5*5*5-5*5
100=(5+5+5+5)*5
Problem 5
There are nine cards with different
digits 1,2,3,4,5,6,7,8,9.
Can you compose number 100 using all
these cards in the same order and the
arithmetic operations +, -, *, and / ?
Answers
100=1+2+3+4+5+6+7+8*9
100=1*23+4+5+67-8+9
Problem 6
Can you replace # by arithmetic
operations so that the following
expression will be equal to 100? You
can use parentheses.
1#2#3#4#5
Answer
100=1*(2+3)*4*5
Problem 7
Jerry has four cards with the digit 2.
How can he arrange these cards to
get 0, 1, 2, 3, 4, 5, 6, 8, 9, or 10?
Jerry can use arithmetic operations
+, -, *, and /.
Answer
22-22=0
22:22=1
2:2+2:2=2
(2+2+2):2=3
2*2+2-2=4
Answer /continued/
2*2+2:2=5
2*2*2-2=6
2 +2+2+2=8
22:2-2=9
2*2*2+2=10
Problem 8
Can you put in parentheses so that this
expression will be equal to 23?
7*9+12:3-2
Answer
23=(7*9+12):3-2
Problem 9
Can you put parentheses in the same
expression to make it equal to 75?
7*9+12:3-2
Answer
75=(7*9+12):(3-2)
Problem 10
Put numbers into this table so that the sum
of any three adjacent cells equals 15.
6
4
Answer
The number in each cell must be the same
as the number in any cell three slots away
from it. Let’s fill the table step by step.
6
6
6
4 6
6
6
4 6
4 6
4 6
4 6
6 5 4 6 5 4 6 5 4 6 5 4 6