(2.8 multiply 10^-3)-(0.65multiply10^-4)+(0.15multiply10^-2
Answers
Answer:
Step 1: Set the multiplication out as follows.
6 0 3
× 5 8
Note that the number with the smaller number of digits goes at the bottom.
Step 2: Multiply 603 by 8.
6 0 3
× 5 8
4 8 2 4
The result of 8 × 603 is shown in bold.
Step 3: Next, multiply 603 by 50. This is the same as multiplying 603 by 5 and by 10. We place a zero to the right and then write down the result of 5 × 603.
6 0 3
× 5 8
4 8 2 4
3 0 1 5 0
The result of 5 × 603 is shown in bold and the additional zero has been shown in blue.
Step 4: Finally, add these two rows together to give the final answer.
6 0 3
× 5 8
4 8 2 4
3 0 1 5 0
3 4 9 7 4
The final answer for 58 × 603 is 34974.
These techniques can be extended to numbers with any number of digits and to numbers involving decimals. For example, if the sum were 5.8 × 6.03, notice that there are 3 digits after the decimal point in total in the sum.
The answer would also have three digits after the decimal point, so instead of 34974,
5.8 × 6.03 = 34.974
Using the same rules for numbers with decimal points:
5.8 × 60.3 = 349.74
58 × 6.03 = 349.74
5.8 × 0.603 = 3.4974