Actually, the answer is obvious Xiaoming borrowed 490 from his father and 490 from his mother.
490+490 equals 980-buying shoes is 970, so the remaining 10 yuan, and the missing 10 yuan is just an illusion and does not exist at all.
Operational properties of division
1, the dividend is enlarged (reduced) by n times, and the quotient is correspondingly enlarged (reduced) by n times under the condition that the divisor is unchanged.
2. The divisor is expanded (reduced) by n times, while the dividend is unchanged, and the quotient is correspondingly reduced (expanded) by n times.
3. Dividing the dividend by two divisors is equal to dividing by the product of these two divisors.