How do you use estimation to check the sum of 437 and

529?

In this lesson you will learn to check if your answers to story problems are reasonable by using front end estimation.

Let’s ReviewLet’s Review

Reasonable means it makes sense.

Let’s ReviewA Common Mistake

Not completing all steps in multi-step problems and not checking back to see

if the answer makes sense.

Let’s ReviewCore Lesson Front end estimation

Look at the first digit

437The 4 is in the hundred’s place so it’s

value is 400.

Rounding to the lead digit

Let’s ReviewCore Lesson Prove with place value tools 437

Let’s ReviewCore Lesson

437 using front end estimation is 400.

Rounding to the lead digit.

Let’s ReviewCore Lesson Front end estimationRounding to lead digit

Look at the first digit

529The 5 is in the hundred’s place so it’s

value is 500.

Let’s ReviewCore Lesson Prove with place value tools 529

Let’s ReviewCore Lesson

529 using front end estimation is 500.Rounding to the lead digit.

Let’s ReviewCore Lesson

4 3 7+ 5 2 9

9 6

1

6

4 0 0+ 5 0 0

9 0 0

Let’s ReviewCore LessonJack baked 232 cupcakes. Jill baked 318 cupcakes.

They sold 115. How many do they have left?

Jack 232 cupcakes. Jill 318 cupcakes.They sold 115.

Let’s ReviewCore Lesson Jack 232 cupcakes. Jill 318 cupcakes.They sold 115.

232 + 318 -115 = How many cupcakes are left

2 3 2+ 3 1 8

5 0

1

5

5 5 0- 1 1 5

4 5

4

3 cupcakes are left

Let’s ReviewCore Lesson

Jack 232 cupcakes. 200 Jill 318 cupcakes. 300

They sold 115. 100

232 + 318 -115 = 435 cupcakes are left 200 + 300 -100 = 400 cupcakes are left

In this lesson you have learned to check if your answers to

story problems are reasonable by using front end estimation.

Let’s ReviewGuided Practice

Third grade is collecting canned goods for the food pantry. The goal is 1000 cans. In week one 122 cans were collected. In week two 315 cans were collected. In week three 450 cans were collected. How many are still needed to reach the goal?

Let’s ReviewGuided Practice

Goal is 1000 cans

Cans collected:Week one: 122Week two: 315Week three: 450+

Let’s ReviewExtension Activities“ Story Problem Mix-Up”Needed: 3 players and scrap paper stripsTo Play: (play 3 rounds each player leads one)-First player gives a topic (like the can drive)-all players write a sentence including a number and action to go with the topic-first player creates a story with all sentences-each player solves, showing strategies used-CHECK for reasonable answer using front end estimation! Compare and discuss

Let’s ReviewExtension Activities

Story Problem Bank

As players finish rounds of play in Story Problem Mix Up, record the story problems and file so partners or individual students can work on just solving and then checking using front end estimation.

Let’s ReviewExtension Activities

Front End Estimation Roll-a- thon!

Needed: 3 players, 3 dice, paperTo Play: each player gets 1 roll per roundChoose 2 or 3 dice, before roll say add or subtract. Keep track of each play. When all players have gone solve the equation. Use front end estimation to check if answer is reasonable. Compare and discuss.

Let’s ReviewQuick QuizJack and Jill need to bring 500 pails up the hill. Jack carried 224. Jill carried 231. They spilled 112!

1. Select the equation that tells how many more they need to carry?

2. Select the equation that uses front end estimation to check.