Lesson # 7
Decimals written as money !
When doing operations with decimals…
• Think about MONEY !
If you said…
$0.05 is …half a dollar…or half a cent…or 5 bucks……then…
$0.05 is equal to 5 cents.
Another example…
• $0.025 is equal to…
A) A quarter
B) Two and a half cents
C) Twenty five cents
D) Two dollars and fifty cents.
If you said that $0.025 is equal to
B) Two and a half cents, then you are right!
So…
• When adding, subtracting, multiplying or dividing …
• Numbers with DECIMALS….
$0.015 = one and a half cents
• Soooooooooo
0.015 + 0.015 equals…
• One and a half cents PLUS one and a half cents…
• ( 0.03) Three Cents !
An example of subtracting…
• $1.25 – $0.05 = ?
Think…
• $1.25 equals one dollar and twenty five cents…
• Subtract…
• $0.05 (a nickel)
• Therefore $1.25 - $0.05 = $1.2 (One dollar and twenty cents)
An example of Multiplying…
0.12 x 2.0 = ?
Convert the “friendliest” number into groups and the other to
MONEY!
0.12 x 2.0
• Make the 0.12 the money (12 cents)
• Make the 2.0 the number of groups
That means you have …
• Two groups of 12 cents…
• Which is 24 cents ( 0.24) !
Think…
0.35 (35 cents) ÷ 0.05(5 cents)
How many times would…
• Five cents fit into 35 cents?
Lets get ready for 12 practice questions !
• That’s right “12” ,
• 3 add,• 3 subtract,• 3 multiply and• 3 divide.