38
Section 1 Whole Numbers
Copyright by The Goodheart-Willcox Co., Inc.
For larger equations like this one, neatness is important. When multiplying the next set of
numbers, write the carried numbers above the previously used carried numbers. Keep careful
track of these numbers, so you do not add the wrong numbers. In larger equations, you may
want to cross out carried numbers after they have been used in a calculation.
1 1
6 5
298
× 27
2086
596
8,046
Accurate Alignment
Be sure to line up the numbers accurately in your answer. You may include right-hand
zeros or X’s to help keep the figures aligned. These zeros and X’s occupy the space of indented
columns.
154
Zeros added to
keep columns aligned.
154
X’s added to keep
columns aligned.
× 368 × 368
1232 1232
9240 924X
46200 462XX
56,672 56,672
Notice the emboldened zeros and Xs in the examples above. Including such characters will
help to keep your columns properly aligned. Leaving those spaces open may lead to column
confusion and incorrect results.
Checking Multiplication by Reversing Positions
A method of checking your multiplication work is to reverse the positions of the multiplier
and multiplicand and repeat the problem. Performing the equation each way should result
in the same product. The numbers obtained by multiplying each digit of the multiplier with
the multiplicand will be different than the numbers from the first equations. However, these
different numbers should still add up to the same final product as the original equation.
Original
Equation
Reverse Position
Equation
643 972
× 972 × 643
1286 Different 2916
45010 Different 38880
578700 Different 583200
624,996 Same 624,996
As shown in the example above, the initial multiplication results may be different, but the final fi
product should match the original answer.