1, sum and difference problem
It is known that the sum of two numbers is 10, and the difference is 2. Find these two numbers.
Formula: sum plus difference, the bigger it becomes; Divided by 2, it is big;
And subtract the difference, the smaller the reduction; Divided by 2, it is small. ?
According to the formula, large number =( 10+2)÷2=6 and decimal number =( 10-2)÷2=4.
2. Difference ratio problem
The number a is greater than the number b 12, and A: B = 7: 4. Find two numbers.
Formula: I am more than you, and multiple is cause and effect.
Actual difference of numerator, multiple difference of denominator.
Double the quotient and multiply it by their respective multiples to get two numbers. ?
First, double the amount, 12/(7-4)=4,
So the number A is 4X7=28 and the number B is 4X4= 16.
3. The problem that chickens and rabbits are in the same cage
Chickens are free in the same cage, with head 36 and feet 120. Find the number of chickens and rabbits.
Formula: Suppose all chickens, suppose all rabbits.
How many feet are there? How many feet are missing?
Divided by the foot difference, it is the number of chickens and rabbits. ?
When finding rabbits, it is assumed that they are all chickens, so the number of exemptions =( 120-36X2)÷(4-2)=24.
If all chickens are rabbits, then the number of chickens = (4x36-120)/(4-2) =12.
4. Profit and loss issues
Children are divided into peaches, each 10, 9 less; Eight more than seven per person. How many children and peaches are there?
Formula: all profits are all losses, and the big one is deducted from the small one; One profit and one loss, the profit and loss add up.
Divided by the difference in distribution, the result is something or people distributed.
The formula is: (9+7)÷( 10-8)=8 (person), and the corresponding peach is 8X 10-9=7 1 (person).