Page 145 - NUMINO Challenge_C1
P. 145
Answer
Key
Problem solving 2 Form a 2-digit number with two number cards
1 23 must be subtracted from 123. Add 63 and and use the remaining cards in order to make 10.
12 (3 4 5) 10
subtract 89 to subtract 22 in total. Add 4 and 13 (5 4 2) 10
14 (5 3 2) 10
subtract 5 to subtract 1 in total. 15 (4 3 2) 10
You can also make 10 using multiplication.
123 4 5 67 89 100 5 2 1 (4 3) 10
5 3 (4 2 1) 10
2 The sum of the numbers from 1 to 9 is 45. When 4 3 (5 2 1) 10
1 4 2 (5 3) 10
you form the 2-digit number by putting Answers will vary.
and together, the sum becomes 45
. Since 108 is greater than 45 by
63, 63. Since 78 7 8 63,
put 7 and 8 together to form the number 78.
1 2 3 4 5 6 78 9 108 3 1000 must be made using only addition, so the
number added must be smaller than 1000.
888 88 88 88 8. 888 is preferred
Creative Thinking p.30~p.31 (since you have to use the least number of 8’s),
as it is the number closest to 1000 using only 8’s.
1 If you put in all the , the result is 45. If you The difference between 1000 and 888 is 112.
change into , the sum becomes smaller by The number closest to 100 using only 8's is 88.
two times the number subtracted. So you must
subtract 22 to make the sum smaller by 44. You The remaining 112 88 24 can be made by
cannot subtract 9 because it is the first number.
So in order to subtract 22 from the numbers adding 8 three times. Therefore, to make 1000
between 1 and 8, put in front of (8, 7, 5, 2)
(8, 7, 6, 1) (8, 7, 4, 3) (8, 7, 4, 2, 1) (8, 6, 5, 3) (8, with the least number of 8's, you must form
6, 5, 2, 1) (8, 6, 4, 3, 1) (8, 5, 4, 3, 2) (7, 6, 5, 4)
(7, 6, 5, 3, 1) (7, 6, 4, 3, 2) (7, 5, 4, 3, 2, 1) 888 88 8 8 8 1000 and use 8 eight
9876543211 times.
9876543211
Answers will vary. 4 To get the greatest possible answer, you must
multiply the two greatest numbers, which are 16
and 8. 16 8 4 2 1 130
To get the smallest possible answer, you must
make the number you subtract or divide as large
as you can. 16 8 4 2 1 1
NUMINO Challenge C1
Key
Problem solving 2 Form a 2-digit number with two number cards
1 23 must be subtracted from 123. Add 63 and and use the remaining cards in order to make 10.
12 (3 4 5) 10
subtract 89 to subtract 22 in total. Add 4 and 13 (5 4 2) 10
14 (5 3 2) 10
subtract 5 to subtract 1 in total. 15 (4 3 2) 10
You can also make 10 using multiplication.
123 4 5 67 89 100 5 2 1 (4 3) 10
5 3 (4 2 1) 10
2 The sum of the numbers from 1 to 9 is 45. When 4 3 (5 2 1) 10
1 4 2 (5 3) 10
you form the 2-digit number by putting Answers will vary.
and together, the sum becomes 45
. Since 108 is greater than 45 by
63, 63. Since 78 7 8 63,
put 7 and 8 together to form the number 78.
1 2 3 4 5 6 78 9 108 3 1000 must be made using only addition, so the
number added must be smaller than 1000.
888 88 88 88 8. 888 is preferred
Creative Thinking p.30~p.31 (since you have to use the least number of 8’s),
as it is the number closest to 1000 using only 8’s.
1 If you put in all the , the result is 45. If you The difference between 1000 and 888 is 112.
change into , the sum becomes smaller by The number closest to 100 using only 8's is 88.
two times the number subtracted. So you must
subtract 22 to make the sum smaller by 44. You The remaining 112 88 24 can be made by
cannot subtract 9 because it is the first number.
So in order to subtract 22 from the numbers adding 8 three times. Therefore, to make 1000
between 1 and 8, put in front of (8, 7, 5, 2)
(8, 7, 6, 1) (8, 7, 4, 3) (8, 7, 4, 2, 1) (8, 6, 5, 3) (8, with the least number of 8's, you must form
6, 5, 2, 1) (8, 6, 4, 3, 1) (8, 5, 4, 3, 2) (7, 6, 5, 4)
(7, 6, 5, 3, 1) (7, 6, 4, 3, 2) (7, 5, 4, 3, 2, 1) 888 88 8 8 8 1000 and use 8 eight
9876543211 times.
9876543211
Answers will vary. 4 To get the greatest possible answer, you must
multiply the two greatest numbers, which are 16
and 8. 16 8 4 2 1 130
To get the smallest possible answer, you must
make the number you subtract or divide as large
as you can. 16 8 4 2 1 1
NUMINO Challenge C1
