Page 93 - NUMINO Challenge_M2
P. 93
4. Four Fours
Placing Operation Symbols
In an expression with multiple + signs, when a + sign is changed to a -
sign, the result is decreased two times more than the number that is
changed to a - sign.
Making Numbers
Various numbers can be made with the given numbers and the operation
symbols +, -, and ^.
2-1 1 2^1 2 2+1 3
12 6 6- 2 4 6- 1 5 6 ^ 1 6
+-^ 6+ 1 7 6+2 8
6+2 + 1 9
EExxpplloorree Complete the expression by placing + or - sign in each .
43214
4+3+2+1=10. To make the result 4, the + sign must be
changed to - sign.
In order to change the result from 10 to 4, the operation symbol
in front of the 3 is changed from + sign to - sign:
4-3+2+1=4.
Since 2+1=3, the + sign can be changed to - sign in front of
both 2 and 1: 4+3-2-1=4.
EExxeerrcciissee Complete the expression by placing +, -, and ^ only once.
4 3 2 1 11
90 NUMINO Challenge M2
Placing Operation Symbols
In an expression with multiple + signs, when a + sign is changed to a -
sign, the result is decreased two times more than the number that is
changed to a - sign.
Making Numbers
Various numbers can be made with the given numbers and the operation
symbols +, -, and ^.
2-1 1 2^1 2 2+1 3
12 6 6- 2 4 6- 1 5 6 ^ 1 6
+-^ 6+ 1 7 6+2 8
6+2 + 1 9
EExxpplloorree Complete the expression by placing + or - sign in each .
43214
4+3+2+1=10. To make the result 4, the + sign must be
changed to - sign.
In order to change the result from 10 to 4, the operation symbol
in front of the 3 is changed from + sign to - sign:
4-3+2+1=4.
Since 2+1=3, the + sign can be changed to - sign in front of
both 2 and 1: 4+3-2-1=4.
EExxeerrcciissee Complete the expression by placing +, -, and ^ only once.
4 3 2 1 11
90 NUMINO Challenge M2
