Mental Math
.4 x .5
.20
1.17 x .4
.468
A recipe calls for 0.75 cups of sugar, and the price of sugar is $1.20 per cup. How much will it cost to buy the sugar?
$0.90
How many decimal place values are in the answer for .7 x .2
2 decimal place values
Jenna is shading a decimal model to solve .5 x .4
How many columns and how many rows should she shade on a decimal square to show this equation?
5 columns and 4 rows
.6 x .6
.36
.13 x .2
.026
Sarah is buying pens for her stationery store. Each pen costs $2.45, and she plans to buy 36 pens. How much will Sarah spend on the pens?
Sarah will spend $88.20
How many decimal place values are in the answer for .27 x .2
3 decimal place values
Mrs. Romero is shading a decimal model to solve .6 x .2
How many double-shaded squares would she count to get the product?
12 squares
.25 x .4
.100
42.3 x .07
2.961
Sam has .25 of a chocolate bar. Of the .25 he gives .3 to a friend. How much of the chocolate bar does he give his friend?
.075
How many decimal place values are in the answer for .72 x .22
4 decimal place values
Mrs. Schettino is shading a decimal model to solve .5 x .3
How many double-shaded squares would she count to get the product?
15 squares
.09 x .4
.036
.15 x .8
.120
Lena is making custom tablecloths for an event. She buys fabric that costs $3.75 per meter. If she buys 12.5 meters of fabric, how much will she spend in total? Round to the nearest hundredth
$3.75 × 12.5 = $46.875
so Lena will spend $46.88
Mrs. Sarcone is solving 2.34 x .3
How many decimal place values will be in the answer? HOW DO YOU KNOW? Explain
3 decimal place values because the first factor has 2 decimal place values and the second factor has 1 decimal place value. 2 + 1 = 3, totaling 3 decimal place values all together.
Mrs. Williams is shading a model to solve a decimal multiplication problem. She shades 7 columns and 4 rows. What is the equation that she is solving for? (Don´t forget to include the product)
.7 x .4 = .28
.20 x .4
.080
.125 x .2
.0250
John works as a freelance graphic designer. He charges $45.75 per hour for his services. If he works for 12.5 hours in a week, how much will he earn in total? Round to the nearest hundredth.
John will earn $571.88
$571.875 rounded to the nearest hundredth is $571.88
Kayla says that when solving .3 x .3 , there will be a total of 1 decimal place value in the answer since both factors are the same and each have one digit after the decimal point. Is she correct? Explain
Kayla is incorrect because you need to add the total amount of decimal place values in the factors. If each factor has one decimal place value then there are two decimal place values all together.
Jon is shading a decimal model to solve the problem .9 x .2
After shading he says that the answer is 18 because he has counted a total of 18 double-shaded squares. Jenna says he is incorrect. Explain to Jon why his answer is wrong.
Each small square on a decimal model represents one hundredth, so a total of 18 double-shaded squares makes the answer .18 not 18 wholes.