Multiplying a three digit decimal by a one decimal number (for example 0.529 * 0.7)
involves several steps.
- Place one decimal above the other so that they are lined up on the right side.
Draw a line under the bottom number. Temporarily disregard the decimal points and
multiply the numbers like you would multiply a three digit number by a one digit number.
0.529
0.7
- Multiply the two numbers on the right side. (9 * 7 = 63). This number is larger
than 10 so place a six above the center column and place three below the
line in the right column.
0.529
0.7
- Multiply the digit in the top center column (2) by the digit in the lower right
column (7). The answer (2*7=14) is added to the 6 above the center
column to give an answer of 20. The units place value (0) of 20 is placed below
the line and the tens place value (2) of the 20 is placed above the five.
6
0.529
0.7
3
- The five of the top number is multiplied by the seven of the lower multiplier
(5*7=35). The two that was previously carried is added and the 37 is placed below
the line. At the start we disregarded the decimal
points. We must now count up the decimal places and move the decimal place to its
proper location. We have three decimal places in 0.529 and one in the decimal 0.7 so
we move the decimal four places to the left to give the final answer of 0.3703.
6
0.529
0.7
03