number sense

Question

DEDRA adds 3 dimes, 4 quarters, and 7 nickels into a money jar. Dedra then takes out 1 quarter and 6 dimes the next day. Write an expression that shows how the overall amount of money in the jar increased or decreased. then simplify the expression.

Answer 1

A dime is worth 10 cents ($0.10), a nickel five cents ($0.05), and a quarter 25 cents ($0.025)

 

$$ added to jar = 3*($0.10) + 4*($0.25) + 7*($0.05)

 

$$ taken out of jar = 1*($0.25) + 6*($$0.10)

 

Overall $$ increase/decrease = $$ added to jar - $$ taken out of jar

 

= 3*($0.10) + 4*($0.25) + 7*($0.05) - [1*($0.25) + 6*($$0.10)]

 

= 3*($0.10) + 4*($0.25) + 7*($0.05) - 1*($0.25) - 6*($$0.10)

 

= 3*($0.25) + 7*($0.05) - 3*($0.10) = $0.80

 

 

Answer 2

I like to work in cents (decimals tend to be easy to mess up).

 

Total in jar originally

3(10)+4(25)+7(5) = 30+100+35 = 165 cents

 

Total taken out

1(25)+6(10) = 25 + 60 = 85 cents

 

165-85=80 cents