Question

用简便方法计算78乘99

Answer 1

答：原式=(100-1)×78=7800-78=7722

Answer 2

78×99=78×(100-1)=7800-78=7800-(80-2)=7802-80=7722

Answer 3

78×99
＝78×（100-1）
＝78×100-78×1
＝7800-78
＝7722

Answer 4

78*99=78*(100-1)=7800-78=7722

Answer 5

78*(100-1)=7800-78=7722