How do you round 349 to the nearest 100?

Will 349 round to 300 or 400?

In this lesson you will learn how to round to the nearest

100 by using base ten blocks.

Let’s ReviewLet’s Review

Base Ten Blocks

OnesTensHundredsThousands

Let’s ReviewLet’s Review

Thousands Hundreds Tens Ones

2 4 6 7

Let’s ReviewA Common Mistake

Knowing when to round up or round down.

It is important to consider the number size and the benchmark numbers when

rounding.

Let’s ReviewCore Lesson

Rounding - To find a number that is close to a given number.

My family drove 323 miles on

vacation.

We drove about 320 miles.

Let’s ReviewCore Lesson

1 2 3 4 5 6 7 8 9 10

11 12 13 14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30

31 32 33 34 35 36 37 38 39 40

41 42 43 44 45 46 47 48 49 50

51 52 53 54 55 56 57 58 59 60

61 62 63 64 65 66 67 68 69 70

71 72 73 74 75 76 77 78 79 80

81 82 83 84 85 86 87 88 89 90

91 92 93 94 95 96 97 98 99 100

Numbers less than the midpoint round down.

Numbers the same as or greater than the midpoint round up.

Let’s ReviewCore Lesson

Round 345 to the nearest hundred.

345 is between 300 and 400.

Let’s ReviewCore LessonRound 345

to the nearest 100.

100 200

300 400

The midpoint is 350.

Let’s ReviewCore Lesson

Round 564 to the nearest 100.

564 – = 500564 + = 600

6436

564 is between 500 and 600.

The midpoint of 500 and 600 is 550.

In this lesson you have learned how to round to the nearest

100 by using base ten blocks.

Let’s ReviewGuided Practice

1). Round 349 to the nearest hundred.

Let’s ReviewExtension Activities

Create the following numbers with base ten blocks. Round each number to the nearest 100.

165 247 1,152 85

Let’s ReviewExtension Activities

In your math journal, explain how to determine if a number rounds up or rounds down.

Round these numbers to the nearest 100.

631 790 1,482

Let’s ReviewQuick Quiz

1). Round 237 to the nearest 100.

2). Round 2,864 to the nearest 100.