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Two-digit times two-digit carry
Based on the vertical calculation of two-digit multiplication by two-digit decimal, which the third-grade pupils have learned, students are guided to summarize and practice the vertical calculation of two-digit multiplication by two-digit decimal.

vertical

Vertical type means that each transition number is changed by the last transition number, and then the single digits of the last transition number are multiplied by 2. If carry is needed, proceed to 1, then increase the unit number by ten digits, and so on, and add a new operand to the unit number.

Calculation of vertical multiplication of two digits;

Digital calibration, unit multiplication. First multiply the multiplicand by the multiplier digits, and the last digit of the number is aligned with the multiplier digits. Then multiply the multiplicand by the number on the tenth bit of the multiplier, and the last bit of the number is aligned with the tenth bit of the multiplier. Then add up the products of the two times.

An example of vertical calculation of multiplying two digits by two digits;

25× 12=300 checking calculation: 300÷25= 12. Note: Each transition number is changed from the previous transition number, and then the single digits of the previous transition number are multiplied by 2. If carry is needed, advance 1, then increase the unit number by ten digits, and so on, and add the new operand to the unit number. Vertical calculation method. ?

If the sum exceeds 10, proceed to 1. (The numbers should be aligned. Subtraction: Same number alignment. If it is not enough, borrow 1 from the last digit as 10. Multiplication: the 1 bit of one number is multiplied by the 1 bit of another number, and the text 1 is multiplied by two digits. ..