Add type:
1, knowing one part and the other part, find the total.
Example: Xiaoming keeps 8 gray rabbits and 4 white rabbits at home. How many rabbits does a * * * have?
Think: One part (8 gray rabbits) and the other part (4 white rabbits) are known. Find the total.
Formula: 8+4= 12 (only)
2. Given the decimal and the difference, find the larger number.
Example: Xiaoli's family has 4 domestic white rabbits, and there are 3 more gray rabbits than white rabbits. How many gray rabbits are there?
Thinking: Knowing the sum of decimal (4 white rabbits) and phase difference (3 gray rabbits are more than white rabbits), find the large number. (Only the number of grey rabbits. )
Formula: 4+3=7 (only).
Types of subtraction:
1, know the total and part of it, and find the other part.
Example: Xiao Li keeps 12 rabbits, including 8 white rabbits and the rest are gray rabbits. How many gray rabbits are there?
Think about it: we know the total number (12 rabbits), and one part (8 rabbits), and find the other part (how many gray rabbits are there? )
Formula: 12—8=4 (only).
2. Given the sum and difference of large numbers, find the decimal number.
Example: Xiao Qiang has eight white rabbits, three of which are more than gray rabbits. How many gray rabbits are there?
Thinking: Given the large number (8 white rabbits) and the difference (3 white rabbits are more than gray rabbits), find the decimal number (how many gray rabbits are there? )
Formula: 8-3 = 5 (only).
3, known large numbers and decimals, seek the difference.
Example: Xiao Yong has 8 white rabbits and 5 gray rabbits. How many white rabbits are there more than gray rabbits?
Thinking: Know the large number (8 rabbits) and the decimal number (5 gray rabbits) and find the difference. How many white rabbits are there more than gray rabbits? )
Formula: 8-5 = 3 (only).
Type of multiplication:
1, and the number of shares per share is known. Find the total.
Example: Xiaoli keeps 6 cages of rabbits, 4 rabbits in each cage. How many rabbits does a * * * have?
Thinking: Given each serving (4 rabbits) and each serving (6 cages), find the total number (one * * *, how many rabbits have been raised? ) that is, how many are six fours. Calculate by multiplication.
2. What is the multiple of a number?
Example: There are 8 white rabbits, and the number of grey rabbits is twice that of white rabbits. How many gray rabbits are there?
Think about it: there are eight white rabbits, and the number of gray rabbits is twice that of white rabbits. That is to say, there are only two white rabbits in the gray rabbit, so how much are two eights?
Classification type:
1, the total number of copies and the number of copies are known, so find each number of copies.
There are 15 apples in Xiao Qiang, which are put on three plates on average. How many apples are put on each plate on average?
Think: the total number is known (15), and the number of copies is known (put 3 disks). How many copies per plate? ) that is, divide 15 into three parts on average and work out how much each part is.
2. Know the total number and each copy, and ask for the number of copies.
For example, there are 15 apples in Xiao Qiang. How many apples can he put in every five?
Question: Because the total number (15 apples) and each serving (5 apples per plate) are known, how many plates can you put? In other words, how many fives can be put in 25?
3. Find out how many times one number is another.
Xiao Yong has 15 apples and 5 pears. How many times are there more apples than pears?
Think about it: Look at the number of apples. There are several pears, which are several times as many as pears. That is, how many times one number is another.
4. Know how many times a number is and find this number.
For example, Xiao Yong has 15 apples, and the number of apples is three times that of pears, so how many pears are there?