D. Dividing a whole Number by a whole Number with a Decimal Quotient
(a) Rita’s mother backed a cake and cut it into 8 pieces. Rita took 5 pieces to share with her friends in school. How would you express the amount Rita took to school as a fraction and then as a decimal?
5/8 as a fraction
5÷8 = ?
8 ) 5 ( 8 ) 5.0 ( .
Answer: Rita took 5/8 or 0.625 of the cake to school.
(b) 7÷4 = ?
Answer: 7÷4 =1.75
Dividing by Decimal Numbers
Look at this division of a whole number. 7 ) 28 ( 4
Multiply both the dividend by 10. 70 ) 280 (4
Multiply both the divisor and the dividend by 100. 700 ) 2800 (4
The quotient has changed.
You can use this idea to help you divide by decimals.
When you divide by decimals, you need to first change the divisor into a whole number.
(a) 0.76÷04 = ?
Step 1. Multiply the decimal divisor by a multiple of 10 to make it a whole number. 0.4×10 = 4
Step 2. Multiply the dividend by the same multiple of 10. 0.76×10 =7.6
Step 3. Divide as usual.
Answer: 0.76÷0.4 = 1.9