Solution - Long multiplication

Start by multiplying the ones digit (9) of the multiplier 9 by each digit of the multiplicand 86,423, from right to left.

Multiply the ones digit (9) of the multiplicator by the number in the ones place value:
9×3=27

Write 7 in the ones place.

Because the result is greater than 9, carry the 2 to the tens place.

Multiply the ones digit (9) of the multiplicator by the number in the tens place value and add the carried number (2):
9×2+2=20

Write 0 in the tens place.

Because the result is greater than 9, carry the 2 to the hundreds place.

Multiply the ones digit (9) of the multiplicator by the number in the hundreds place value and add the carried number (2):
9×4+2=38

Write 8 in the hundreds place.

Because the result is greater than 9, carry the 3 to the thousands place.

Multiply the ones digit (9) of the multiplicator by the number in the thousands place value and add the carried number (3):
9×6+3=57

Write 7 in the thousands place.

Because the result is greater than 9, carry the 5 to the ten thousands place.

Multiply the ones digit (9) of the multiplicator by the number in the ten thousands place value and add the carried number (5):
9×8+5=77

Write 7 in the ten thousands place.

Because the result is greater than 9, carry the 7 to the hundred thousands place.

The solution is: 777,807