Decimal Operations How To

What is the correct first step when adding 4.23 and 2.7?

• Subtract the smaller number from the larger number.

• Align the decimal points and add the numbers directly.

• Convert the decimals to fractions before adding

• Round each decimal to the nearest whole number before adding

What is the correct procedure for multiplying 0.40 by 0.75?

• Add the numbers first, then multiply the sum by the decimal places

• Subtract one number from the other, then multiply the result by the decimal places.

• Multiply the numbers as if they were whole numbers, then place the decimal point based on the total number of decimal places in the factors.

• Convert the decimals to fractions, multiply the fractions, and then convert back to a decimal.

When adding 3.456 and 7.8, what should you do first?

• Round both decimals to the nearest whole number before adding.

• Align the decimal points and add zeros to the end of the shorter decimal to match the number of decimal places.

• Convert the decimals to fractions and add the fractions.

• Subtract the smaller decimal from the larger decimal before adding.

How should you prepare to subtract 15.2 from 23.456?

• Convert both decimals to whole numbers before subtracting

• Align the decimal points, small number on top, and add zeros to the end of the shorter decimal.

• Round both decimals to one decimal place before subtracting

• Align the decimal points, bigger number on top, and add zeros to the end of the shorter decimal.

What is the correct process for multiplying 2.5 × 4.6?

• Align decimals and multiply like normal, drop down decimal at the end

• Add the numbers before multiplying

• Multiply the numbers as if they were whole numbers, then count the total number of decimal places in both factors to place the decimal point in the product

• Bigger decimal goes on top, multiply like normal

What should you do when dividing 9.36 by 0.6?

• Bigger number goes inside and divide like normal. Ignore the decimals completely.

• Move the decimal point in the divisor to make it a whole number and move the decimal point in the dividend by the same number of places

• Align decimals and divide like you are subtracting

• Multiply the numbers as if they were whole numbers, then count the total number of decimal places in both factors to place the decimal point in the product

25.75 − 7.68 =

• 18.07

• 18.05

• 18.12

• 18.15

15.6 ÷ 0.4=

• 42

• 40

• 41

• 39

0.6 × 4.5=

• 3.0

• 2.7

• 2.4

• 3.5

Alex has the following subtraction problem.

15.75 - 7 =

He set up his problem as shown above. What mistake did he make?