2. Odd number and compound: (9)

3. Even and composite numbers: (4)

Select the cards below to form the required numbers.

1. Choose two cards to form an odd number, and make this odd number as small as possible. This number is (2 1).

2. Choose two cards to form an even number and make this odd number as large as possible. This number is (94).

3. Choose 3 cards to form a number that is a multiple of 3, and make this odd number as large as possible. This number is (92 1).

Fill in the blanks as required.

At 40, 12, 37, 39, 45, 18, 10, 26, 9 1, 69, 234, 76 and 600:

Odd numbers are: (37, 39, 45, 9 1, 69)

Even numbers are: (40, 12, 18, 10, 26, 234, 76, 600).

The multiple of 3 is: (12,39,45,18,69,234,600).

The number with a factor of 5 is: (40,45,10,600).

The prime number is: (37)

The complex number is: (40, 12, 39,45, 18,10,2) 6,91,69,234,76,600).

Test yourself.

1, all multiples of 3. What should I put in ()?

( 1)2 13(0)、2 13(3)、2 13(6)、2 13(9)2

2)68( 1)、4(0)35、 6(0)0(0)

A number is a multiple of 3 and 5. What's the smallest number? 15

A number is a multiple of 2, 3 and 5. What's the smallest number? 30

Fill in the blanks.

1 and 5X7=35, where (35) is a multiple of (5) and (35) is a multiple of (7).

2. Prime number: 21= (2)+(19) = (3) x (7) = (23)-(2)

3. It is a multiple of 2, a multiple of 3 and a multiple of 5. The smallest three digits are (120).