If the most important basis for learning Chinese is words, then the most important basis for learning mathematics is verbal calculation. Teacher Qiu Xuehua, a contemporary educator and special math teacher, once said: "If you want to pass the calculation, you must master the verbal calculation."
Five quick math skills for children to do problems quickly and accurately.
So, how can we calculate quickly and accurately? As long as you master the calculation rules and sequence skillfully, and use reasonable and flexible calculation methods according to the characteristics of the topic itself, you can calculate it quickly and accurately. I'll introduce you to five quick calculation skills:
Five quick math skills for children to do problems quickly and accurately.
1. Method 1: Signed Shift Method
When a calculation problem only has the same level operation (only multiplication and division or only addition and subtraction) without brackets, we can "move with signs"
For example:
23- 1 1+7=23+7- 1 1
4× 14×5=4×5× 14
10÷8×4= 10×4÷8
2. Method 2: Constraint method
Parentheses method
(1) When adding parentheses for addition and subtraction, there is a plus sign in front of the parentheses, a constant sign in the parentheses, a minus sign in front of the parentheses and a sign in the parentheses.
For example:
23+ 19-9=23+( 19-9)
33-6-4=33-(6+4)
(2) When the multiplication and division method is bracketed, the multiplication symbol is in front of the bracket, the constant symbol is in the bracket, the division symbol is in front of the bracket, and the symbol is changed in the bracket.
For example:
2×6÷3=2×(6÷3)
10÷2÷5= 10÷(2×5)
Support removal method
(1) In addition and subtraction, when the brackets are removed, a plus sign is added before the brackets and a minus sign is added before the brackets. When the brackets are deleted, the symbol will change (the original addition in brackets is now reduced; It used to be negative, but now it will be positive.
For example:
17+( 13-7)= 17+ 13-7
23-( 13-9)=23- 13+9
23-( 13+5)=23- 13-5
(2) When removing the brackets in the multiplication and division method, add a multiplication sign in front of the brackets, a constant sign after the brackets, and a division sign after the brackets (the multiplication in the brackets is now divided; It used to be division, but now it's multiplication. )
For example:
1×(6÷2)= 1×6÷2
24÷(3×2)=24÷3÷2
24÷(6÷3)=24÷6×3
3. Method 3: Multiplication and Distribution Law
Distribution method
Parentheses are addition or subtraction operations, multiplied by another number. Pay attention to distribution.
For example:
8×(5+ 1 1)=8×5+8× 1 1
Extraction of common factor method
Pay attention to the extraction of the same factor.
For example:
9×8+9×2=9×(8+2)
4. Method 4: rounding method
See the name, and you will know the meaning of this method. When using this method, we need to pay attention to observation and find the law. Also pay attention to paying back the money. If you borrow it, it is not difficult to borrow it again.
For example:
99+9=( 100- 1)+( 10- 1)
5. Method 5: Split method
Split method is to split a number into several numbers for the convenience of calculation. This requires mastering some "good friends", such as: 2 and 5, 4 and 5, 4 and 25, 8 and 125. Be careful not to change the size of the number when splitting.
For example:
32× 125×25
=4×8× 125×25
=(4×25)×(8× 125)
= 100× 1000
In order to make children skillfully use the quick calculation method, they need to improve their calculation ability through persistent practice, so that they can do their homework and exams with ease.