Putting It Together: Decimals

At the beginning of the module we met Andrew who was throwing a party for his friend Sophia. We want to determine how much he spent on food for the party, here is his list:

  • 3 cakes at $20.15 each
  • [latex]1\Large\frac{1}{2}[/latex] pounds of almonds at $5.99 per pound
  • [latex]\Large\frac{1}{4}[/latex] pound of spices at $7.60 per pound
Metal bin of almonds with a scoop in it.

In the module, we learned how to multiply decimals with integers, fractions and mixed numbers, so we can definitely answer this question using our new skills.

The cost of the three cakes will be:

[latex]3\cdot 20.15=60.45[/latex]

To find the cost of the almonds, we can convert the mixed number to a decimal first, then multiply:

[latex]1\Large\frac{1}{2} = \frac{3}{2} \normalsize = 1.5[/latex] now multiply by the price of the almonds:

[latex]1.5\cdot5.99 = 8.985 = 8.99[/latex] rounding to the nearest cent.

Next, we will find the cost of [latex]\Large\frac{1}{4}[/latex] pound of spices:


[latex]0.25\cdot 7.60=1.90[/latex]

We can sum the three costs together to find the total Andrew spent on extras for the party:


Andrew spent $71.34 on extras for the dinner party.