Page 171 - NUMINO Challenge_M1

Answer
Key

2 There are 20 numbers. If the last number is ,

then -15+1=20, and =34. The largest number is 34.

Type Study The digit 1 is in the ones place in 1, 11, and 21.

The digit 1 is in the tens place in all the numbers from 10 to 19.
10, 11, 12, 13, 14, 15, 16, 17, 18, 19

The digit 1 is in the ones place 3 times and in the tens place 10 times.
3+10=13 times.

Problem solving

1 Find the number of times the digit 3 appears in the ones place and the tens place

separately.

The digit 3 in the ones place: 3, 13, 23, 33
The digit 3 in the tens place: 30, 31, 32, 33, 34, 35, 36, 37, 38, 39

The digit 3 appears 4+10=14 times.

2 In the numbers from 1 to 50; 10 times

The digit 4 in the ones place: 4, 14, 24, 34, 44 5 times
The digit 4 in the tens place: 40, 41, 42, 43, 44, 45, 46, 47, 48, 49

The digit 4 appears 5+10=15 times.
The digit 8 in the ones place: 8, 18, 28, 38, 48
The digit 8 does not appear in the tens place.

The digit 8 appears 5 times.
The digit 4 appears 10 more times than the digit 8.

2. Greater Number, Smaller Number

EEExxxeeerrrccciiissseee The numbers with the greater hundreds digits are 25 and 20 . Between
those numbers, the number with the greater tens digit is 25 . 25 >20
The remaining two numbers have the same hundreds digit, so the number with
the greater tens digit, 14 , is greater than 12 .
25 >20 >14 >12 , and the third greatest number is 14 .

34 NUMINO Challenge M1