Mathematics

Luca Horton

19 May, 11:00

Which strategy would not correctly solve this story problem?

Colin invited 31 people to the picnic. He can fit 10 people at his picnic table and the rest will sit on blankets. Each blanket can hold 3 people.

How many blankets does Colin need so that everyone has somewhere to sit?

A.

Draw a diagram. 10 people at one table, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket, 3 people on a blanket. Count the number of blankets needed.

B.

Work backward. Start with 31 people. Subtract 10. Then subtract 3 to figure out how many blankets will be needed.

C.

Translate into an equation.

(31 - 10) : 3 = b

D.

Use logical reasoning. Start with 31 people, subtract 10 people who will sit at the picnic table, that leaves 21 people. Keep subtracting 3 people until you get to 0. Count how many times you subtracted 3 people.