Mathematics, Numbers and Numerations, Operations (+, -, x, /, etc.)
Grade 1- 3
Students learn to round numbers to the nearest tens, hundreds, and thousands. They also use the concept of rounding in addition and subtraction problems.
Use the number line to introduce the idea of rounding. Color the numbers 10-14 red and the numbers 15-20 blue.
Ask the children if the number 16 is closer to 10 or 20. (The number is in the blue area so it is closer to 20.) Do this with several different numbers to give the children visual practice with rounding.
Review the concept of place value, using the place-value mats and numbered index cards. Give each child a set of index cards and a place-value mat. Shuffle the cards and place in a stack facedown. Take the top four cards, turn them over in order, and lay them on the place-value mat in the same order.
Look at the number in the ones column. Is the 6 closer to 0 tens or 1 ten (10)? (1 ten)
Look at the 76. Is it closer to 7 tens (70) or 8 tens (80)? 0 hundreds or 1 hundred (100)?
Continue in this manner, discussing the various numbers in each column. The basic process is the same. If the number is 0 to 4, round down to the next number. If the number is 5 to 9, round up to the next number.
Introduce how to round numbers and go over the work sheets with the children.
- Round Numbers activity pages
- 50 index cards numbered 0-9 (5 sets of each number)
- number line 10-20
- place-value mat (may be made on a piece of paper, as shown in the example below)