Mathematical multiplication, if there is a carry of the second line, vertical calculation. Two digits are multiplied by the same ten digits and the complementary single digits. Formula: Ten digits plus 1 multiplied by ten digits, and then multiplied by one digit, and written at the back (less than 10 makes up 0). For example: 78×63=49 14. They all follow their own habits. Some people are used to arithmetic later, and they don't write it in place by default.

Mathematical multiplication skills

1, any number multiplied by 1 1. Formula: from left to right, write as much as you can in the high position, then add two and two in turn, carry more than ten, and finally write one bit.

For example: 32618372x11= 358802092.

Write 3 in the high order 3, and then write 3+2=5, 2+6=8, 6+ 1 = 7, 1+8 = 9, 8+3 = 1/(write 1/as/kloc.

2. The operation of multiplying by ten. Formula: the sum of one number plus the tail of another number multiplied by ten, plus the mantissa multiplication is the final result.

For example: 14x 13= 182

( 14+3)× 10= 170,4×3= 12, 170+ 12= 182

18x 17=306

( 18+7)x 10=250，8×7=56，250+56=306

Similarly, you can also use this method to find the square of 1 1 to 19.