Traditional homework and ABC homework cases

600- 199)/ 100

=(6x 100- 1.99 x 100

= 6- 1.99

Example: Law of Constant Difference = 10

=20- 10 =20-(8+2)

20-8-2

:) Simple calculation process (e.g. A-B-C=A-(B+C)

Alphabetic formula: The concept of subtraction property is that one number subtracts two numbers continuously, and the last two numbers can be added first and then subtracted.

Subtraction attribute

= 120

× 10

= 12+3.8)

×(6.2= 12:( 1) 12×6.2+3.8× 12

Simplify the calculation process (example letter formula: (a+b)×c=a×c+b×c)

The concept of multiplication and distribution law is: two numbers are multiplied by a number, which can be multiplied separately and then added.

Powder companion

=3000

× 100

=30×(25×4)

=30:30×25×4

) Simplify the calculation process (for example, letter formula: a×b×c=a×(b×c)

The concept of multiplicative associative law is: multiply the first two numbers, or multiply the last two numbers first, and the product is unchanged.

Multiplicative associative law

= 12000

× 12

= 1000×8× 12

= 125 cases (simplifying the calculation process): 125× 12×8.

Alphabetic formula: a×b=b×a

The concept of multiplicative commutative law is that two factors exchange positions and the product is unchanged.

Commutative law of multiplication

Law of multiplication operation

=26

=6+20

=6+( 18+2)

6+ 18+2

Example (simple calculation process): a+b+c=a+(b+c)

Alphabetic formula: The concept of additive associative law is: first add the first two numbers, or add the last two numbers, and the sum is unchanged.

associative law of addition

=28

= 10+ 18

+ 18

)6+4(=6+ 18+4

Example (simple calculation process): +c

) b+a(a+b+c= letter formula: additive commutative law's concept is that two addends exchange positions and the sum is unchanged.