Home > MC1 > Chapter 2 > Lesson 2.3.1 > Problem2-105

2-105.

Emily and Shilpa were looking at some groups of pennies. Emily sees $3(10)+4$ pennies. Emily thinks there are $42$ pennies, but Shilpa thinks there are $34$ pennies.

1. Who is correct? Why?

Think about what the expression $3(10)+4$ represents. Try finding the answer on your own before looking at the solution.

Shilpa is correct. Three groups of $10$ pennies plus $4$ more pennies is equal to $34$ pennies.

2. Draw a diagram to show the possible arrangement of the pennies. (For help, see Lesson 1.2.1.)

Remember to clearly show the groups and the remaining pennies in your diagram.

3. Describe what a penny diagram might look like for the incorrect answer given by one of the girls above.

Since Emily thinks there are $42$ pennies, draw a diagram which has $3$ groups of $14$.