速算练习

Quick calculation exercises
Collect frequently used quick calculation techniques and generate corresponding questions. Students can practice and look at the help to understand the quick calculation process.
E.g:
Ten times ten times more, formula: head multiplied by head, tail plus tail, tail multiplied by tail.
The head is the same, and the tail is complementary (the tail is added to equal 10): Formula: After adding 1 to a head, the head is multiplied by the head and the tail is multiplied by the tail.
The first multiplier is complementary, and the other multiplier has the same number: formula: after adding 1 to a head, the head is multiplied by the head, and the tail is multiplied by the tail.
The head is complementary (the head is equal to 10), and the tail is the same. The formula: multiply the two digits, add a mantissa to the product, and the number is used as the front product, and the two mantissas are multiplied (that is, the square of the mantissa), and the number is used as the back product. Bit complement 0.

Quick calculation exercises:
1. Choose the type of exercise
2. Enter the exercise, enter the answer, or watch the quick calculation process and help.
3. Support comprehensive exercises.