Clever calculation is to make the calculation simple, rather than sticking to the rules to calculate, which is time-consuming and laborious.

For example, you can calculate 4×58×25 first and then× 58, instead of sequential calculation.

Clever calculation (simple calculation): including the distribution law, associative law and commutative law of multiplication and division. Addition, exchange, combination, etc. This needs to be found in a formula. Find the applicable law and the decomposition number of each number, and you can work out the answer skillfully.

Clever calculation formula of extended data

Multiplication: Distribution Law =ac+ab=a(b+c)

Constraint law =abc=a(bc)

Commutation law =ab=ac

Product Invariant Property =ab=(a÷c)×(bc)(c≠0)

Addition: Law of Association =a+b+c=a+(b+c)

Commutation law =a+b=b+a

Division: a÷b÷c=a÷(b×c)(b≠0, c≠0)

Quotient invariant property = a ÷ b = (a× d) ÷ (b× d) (b ≠ 0, d ≠ 0) = (a ÷ d) ÷ (b ≠ 0, d)

Subtraction: a-b-c=a-(b+c)