First, fill in. ? 1.50 The multiple of 9 is ().

Within 100, the multiple of 19 is (? )。

The factor of 2.25 is (? ), the factor of 65 is ().

3. () is both a factor of 9 and a factor of 12. ?

4. Write five odd numbers () from 199 and five even numbers () from 388.

5. Among nonzero natural numbers within10, () is an even number, but not a composite number; () is odd, but not prime. ?

6. Even number+even number = ()? Odd number+odd number = (? ) odd+even = (? )

7.24= 1×24=2×(? )=(? )×(? )=(? )×( )

8. In the numbers 0, 1, 0.8, 25.2, 35 and -4, the natural number is (? )?

9. Four digits are the smallest prime number in a thousand miles and the smallest composite number in a hundred miles. Ten miles are neither prime nor composite, and there are both odd numbers and composite numbers in the unit. This number is (? )

10. Two digits are both multiples of 3 and 5. What is the minimum quantity? ), the maximum is (? )。 ?

Second, distinguish (tick "√" for the right and "×" for the wrong). ?

Because 7×6=42, 42 is a multiple and 7 is a factor. (? )

Even numbers must have more factors than odd numbers. (? )

The factor of a number must be less than its multiple. (? )

.3, 4 and 5, no matter how they are arranged into three digits, must be multiples of 3. (? )

.

Composite numbers are multiples of 2. (? ) - 2 - ?

Natural numbers are composite numbers other than prime numbers. (? ) 7.3×0.4= 1.2, and 3 is a factor of 1.2. ? (? )

The quotient of a number divided by b number is 15, so a number must be a multiple of b number. ? (? )

Choose one (put the serial number of the correct answer in brackets). ?

1. In the following groups, which group's second number is a multiple of the first number? (? ) A.36 and 9 B.2 10 and 70? C.0.2 and 100? Grass 30 and 60

2. Natural numbers include (? )。 ? A. prime numbers, composite numbers B. factors and multiples C. odd and even numbers

3.2 is the smallest (? )。 ? A. Composite number B. Prime number? C. natural numbers? even number

4. The product of odd number and even number must be (? )。 Odd numbers? Either way is possible.

5. Odd numbers should be (? ), the result can be even. A. multiplied by 3? B. add 2 C. subtract 1?

6. The composite number obtained by multiplying two different prime numbers has at least (? ) factor. ? A.2？ B.3c.1d. Not sure.

Fourth, find and connect. /kloc-a multiple of 0/2? 12 factor? 60 36? 18? 6? 680? 24? 3? 9? 6? 12? - 3 - ? 5. Thinking and writing. ? 1. Write down the factor of each number below, and then write down the multiple of each number (at least four). 9 factor: multiple:? 20? Factor: multiple: 25? Factor: multiple:? 17? Factor: multiple:? 2 1? Factor: multiple: 28? Factor: multiple:? 2. Write the number as required. ? (1) Write five consecutive odd numbers starting from 354. (2) Write five consecutive even numbers from 354. (3) Starting from 354, write five consecutive multiples of 3. ? 3. Guess who I am? ? (1) I am an odd number greater than 3 and less than 7. ? (2) I and another number are both prime numbers, and our sum is 15. (3) I am an even number, and the sum of digits of ten and one is 15. 4. Use 0, 5 and 8 to form three digits:? (1) The factor of this three-digit number is 2:? (2) This three-digit number has a factor of 5:? (3) This three-digit number has both a factor of 2 and a factor of 5:? - 4 - ? 5. Write the rest of the following questions directly without calculation. 497÷2? 86 1÷5? 464÷5? 187÷2 1023÷3? 126÷5? 6. There are 95 pieces of bread. If every two noodles are packed in a bag, can they be packed properly? If you pack a bag every five, can you finish it? If you put one in every three bags, can you finish it? Why? ? 6.( 1) A factor whose number is 48. What could this number be? . (2) A number is both a factor of 48 and a multiple of 8. What's this number? . (3) A number is a factor of 48, a multiple of 8 and a multiple of 3. What's this number? . ? 7. The new library has been opened. Xiaohong goes to the library every three days, and Xiaoling goes every four days. A few days after Xiaohong and Xiaoling met in the library one day, may they meet again in the library for a few days? ? -

5 - ? Reference answer: 1. 1.9? 18? 27? 36 45? 19? 38? 57? 76 95 2. 1? 5? 25 1? 5? 13? 65 3. 1 3? 4.？ 20 1? 203 205? 207? 209 390 392? 394? 396? 398 5.2 9? 6. Even numbers? Odd 7. 12? 3? 8? 6? 4? 8.0? 1? 35? 9.24 19 10. 15 90? Second, x? ×? ×? √ ×? ×? ×? × three, d? c？ b？ b？ c？ b？ Five, three, (1)5? (2) 13+2= 15? (3) Seven of 96 or 78 or 12 days?