1, two integers, the difference is 16, and one is five times that of the other. These two numbers are _ _ _ _ _ and _ _ _ _.

A: 16 (5- 1) = 4, 45 = 20.

2. Fill in the appropriate numbers in brackets according to the law of each series, and say the first, last and number of items.

( 1) 12 1,222,323,424,(),(),(),()

(2)2,3,6,6, 18, 12,(),(),(),()

Answer and analysis:

(1) For arithmetic progression with tolerance of 10 1, fill in 525,626,727,828. The first item is 12 1, and the last item is 828 and 8.

(2) Double series, one is a geometric series with quotient 3 and the other is a geometric series with quotient 2. Fill in 54, 24, 162, 48, the first item 2 and the last item 48, 10.

There is a column of numbers arranged according to certain rules: 3, 7, 8, 6, 3, 7, 8, 6, ... What is the 32nd number in this column? What's the 39th number?

Answer and analysis: 324=8, the 32nd time is 6; 394 = 9 ...3, 39 is 8.

2. Question and answer of Olympiad Mathematics in the second grade of primary school

1, 19 soldiers want to cross the river. There is only one boat, and only four soldiers can sit at a time. How many times must all soldiers cross the river before they can? There are two red socks and two black socks in the bag. How many socks can you take out to make a pair of socks with the same color?

There are four basketballs and four yellow balls in the schoolbag. How many balls must be found to ensure that two balls of different colors can be taken out at once?

Reference answer:

1, 19-4= 15 (name) 4- 1=3 (name) 15÷3=5 (times) 5+ 1=6.

2. If two of them are different colors at one time, touching 1 must be the same color as 1. Therefore, at least three socks must be pulled out at a time to ensure that a pair of socks have the same color.

If you touch four balls of the same color at a time, you must touch a ball of another color, so you can get two balls of different colors by touching at least five balls at a time.

3. Test questions and answers of Olympiad Mathematics in the second grade of primary school

1. Father is 32 years old and son is 4 years old. How many years should it be when the father and son are 50 years old? 50-(32+4)= 14 (year) 14÷2=7 (year)

A: It should be seven years later.

2. Dajun is 6 years old this year, and my mother is five times as big as Dajun. How old was my mother four years ago?

5×6-4=26 (years old) 6-4=2 (years old) 26-2=24 (years old) A: My mother was 24 years older than the army the year before last.

3. There are 28 rabbits in cage A and 6 rabbits in cage B. How can we adjust the number of rabbits in the two cages to be the same? (The total number of rabbits remains the same)

(28-6)÷2= 1 1 (only)

Answer: Cage A gives cage B 1 1 rabbit, and the number of rabbits in both cages is the same.

3. Test questions and answers of Olympiad Mathematics in the second grade of primary school

There are 48 students in two classes, 1 grade, Grade Two. After several girls from Class Two (1) were transferred to Class Two (2), Class Two (1) had fewer students 12 than Class Two (2). How many students are there in Class Two (2) now?

12÷2=6 (person) 48+6=54 (person)

Now there are 54 students in Class Two (2).

2. There are 15 melons in basket A and 27 melons in basket B. Grandpa picked 20 melons and put them in these two baskets. How can I put them so that the number of melons in two baskets is the same? Method 1: Method 2:

27- 15 = 12(a) 15+27+20 = 62

(1)

20- 12=8 (pieces) 62÷2=3 1 (pieces)

8÷2=4 (pieces) 3 1- 15= 16 (pieces)

12+4 = 16(a)3 1-27 = 4(a)

Answer: Only put 16 in the first basket and 4 in the second basket can the number of melons in the two baskets be the same.

3. Children do exercises. The first team has 15 students. After three students were transferred from the second team to the first team, the number of students in the second team was 6 less than that in the first team. How many people are there in the second team?

15+3-6= 12 (people) After the second team transferred three people, the current number is 12+3= 15 (people).

A: The second team originally had 15 people.

4. Question and answer of Olympiad Mathematics in the second grade of primary school

1. Grandpa said to Xiaoming, "I am seven times your age now, six times your age in a few years, five times, four times, three times and two times your age in a few years." Do you know the age of Grandpa and Xiaoming now? Answer:

The age difference between grandpa and Xiaoming will not change. Their age difference is a common multiple of 6, 5, 4, 3 and 2. Considering the practical problem of age, the minimum common multiple is 60. Now grandpa is seven times as old as Xiaoming, so grandpa is 70 years old and Xiaoming 10 years old.

2. There are three trees in a park, and their age consists of two different six numbers, namely 1, 2, 3, 4, 5, 6, and one tree is exactly half the age of the other two trees. Do you know how old these three trees are?

Answer:

The essence of this problem is to divide the six numbers 1, 2, 3, 4, 5 and 6 into three groups, and each group has two numbers to form a two-digit number, so that the sum of the two digits is equal to twice that of the third digit. By the way, it is an important skill to turn interesting problems in life into pure mathematical problems. Students should pay attention to strengthening this ability from an early age, so as to use mathematical knowledge to solve difficult problems in practical work in the future.

After careful observation and bold attempt, three numbers can be obtained by grouping and combining these six numbers: 12,34,56, because 12+56=34×2, that is, the age of these three trees is12,34,56. There are several different answers to this question. Please use your head and find another answer.