Exploring Order in

Mathematics

Put the Cards in Order

Does Order Matter in Mathematics?

3 • 7 = 21 7 • 3 = 21

3 + 5 = 85 + 3 = 8

Commutative Property of Multiplication

Commutative Property of Addition

When order doesn’t matter:

7 – 5 = +25 – 7 = - 2

10 ÷ 5 = 2 5 ÷ 10 = .5

Changing the order yields a different answer:

The FairMs. Delores is taking her children and grandchildren to the fair. Tickets to get in cost $4 each. She paid for 5 grandsons, 2 daughters, and herself.

• How much did Ms. Delores spend on her grandchildren’s tickets? Write an equation and show or explain how you solved the equation.

• Using the two equations you already wrote, write a new equation that gives the total amount Ms. Delores paid for tickets to go into the fair.

• How much did Ms. Delores spend on adult tickets? Write an equation and show or explain how you solved the equation.

Weekend Laundry

I’m doing laundry. I discover $4 in each of three girls’ pockets. The next day, I find $5 in each of 2 different pockets in my husband’s clothes.

3 • 4 + 2 • 5 =

Pay-Day Shopping Splurge

Daijah-Tae went shopping. She bought a scarf for $15, two lip glosses for $7 each, and a cell phone case for $10.

15 + 2(7) + 10

Buffet

Hot food is $7 per pound and salads are $4.50 per pound. You

buy 5 pounds of hot food, 2 pounds from the salad bar, and three waters that are $1 each.

5 • 7 + 2 • 4.5 + 3 • 1

Payroll Costs

Employees Hours Rate of Pay

5 45 $12.002 40 $15.001 40 $27.50

Does Order Matter in Mathematics?