Page 177 - NUMINO Challenge_M1
P. 177
CMYK
Answer
Key
Problem solving
1 The numbers that have a sum of 5 are 0+5=1+4=2+3=5. The tens digit cannot
be zero so the 2-digit numbers whose digits have a sum of 5 are 14, 23, 32, 41, 50.
The numbers greater than 40 are 41 and 50.
2 , , and each represent a different number, so if + =4, then =1, =3 or
=3, =1.
> > , so =3, =1.
Since 3> >1, =2.
The 3-digit number that satisfies the conditions is =132.
Creative Thinking
Count the numbers from 1 to 63 that do not have the digit 4.
Numbers with 4 in the ones place: 4, 14, 24, 34, 44, 54 6 numbers
Numbers with 4 in the tens place: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49
10 numbers
44 appears in both lists, so one number must be subtracted. There are a total
of 6+10-1=15 numbers with the digit 4.
The building has 63-15=48 floors.
Mark's test score is lower than Hank's and higher than Carl's, so it is either 68,
58, or 48. The highest possible test score Mark can have is 68.
In 265>2 7, the digits that can fill are 0, 1, 2, 3, 4, or 5.
The sum of the possible numbers that can fill is 0+1+2+3+4+5=15.
The first, second, and third greatest numbers are as follows.
8 6-8 4-8 0
The fourth greatest number is 68.
8 6 - 8 4 - 8 0-6 8
40 NUMINO Challenge M1
Answer
Key
Problem solving
1 The numbers that have a sum of 5 are 0+5=1+4=2+3=5. The tens digit cannot
be zero so the 2-digit numbers whose digits have a sum of 5 are 14, 23, 32, 41, 50.
The numbers greater than 40 are 41 and 50.
2 , , and each represent a different number, so if + =4, then =1, =3 or
=3, =1.
> > , so =3, =1.
Since 3> >1, =2.
The 3-digit number that satisfies the conditions is =132.
Creative Thinking
Count the numbers from 1 to 63 that do not have the digit 4.
Numbers with 4 in the ones place: 4, 14, 24, 34, 44, 54 6 numbers
Numbers with 4 in the tens place: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49
10 numbers
44 appears in both lists, so one number must be subtracted. There are a total
of 6+10-1=15 numbers with the digit 4.
The building has 63-15=48 floors.
Mark's test score is lower than Hank's and higher than Carl's, so it is either 68,
58, or 48. The highest possible test score Mark can have is 68.
In 265>2 7, the digits that can fill are 0, 1, 2, 3, 4, or 5.
The sum of the possible numbers that can fill is 0+1+2+3+4+5=15.
The first, second, and third greatest numbers are as follows.
8 6-8 4-8 0
The fourth greatest number is 68.
8 6 - 8 4 - 8 0-6 8
40 NUMINO Challenge M1
