The concept of 10 more and 10 less is very important to students' understanding of the place value and number sense. Using hundred charts can help students to understand the logic of ten more and ten less. If the activity is hands on, using base ten blocks, students can see for themselves how easy it is to think about 10 more and 10 less.
|
For this activity, you need hundred charts that match the size of the base ten blocks. Enlarge or reduce your charts until they are slightly larger than the blocks. Students start by making a number with base ten blocks, such as 34. Students see that 34 is made of 3 tens and 4 ones. The base ten blocks are placed on top of the hundred chart, showing that 34 squares have been covered. (Here, the student has used Die-cut Cuisenaire 10s and 1s to represent the base ten blocks).
|
Students are instructed to add ten more by adding another ten block. They discover that when they place the ten down on their chart, ten more is 44. |
Students are instructed to take ten away by removing a ten block. They discover that when they take a ten block away on their chart, ten less is 24. |
The activity can be continued with two tens more (2o more) and two tens less. |
This activity can also be done with clear base ten blocks that also fit together. The blocks connect so that students can connect the ones, tens and hundreds. |
Here, the ones and tens are connected together to make the number 46. |
To show the number ten less than 46, a ten is taken away, showing that 10 less is 36.
|
With the clear base ten blocks, students can see the numbers on the hundreds chart. The student first represented the number 46.
|
To show ten more than 46, a ten is added to the number. Students can see on the hundred chart that 56 is ten more than 46. |
Students must also learn that a number like 34 can be made from 2 tens and 14 ones. This idea readies students for regrouping for addition and subtraction. It also encourages students to think more critically about how numbers are formed. Students could make a number like 34 two or three different ways, using combinations of ones and tens.
After becoming familiar with the logic of moving up a row and moving down a row, students should start understanding the logic of the hundred chart. They should see that moving up a column is 10 less than the original number, and moving down a column is 10 more.
A similar activity can be completed using Kidspiration.
The document is saved at Oakland Terrace in Hand Out for Grades K and 1.
Indicator:
6.1.2.4 model 10 more/less to 100.
6.1.1.1 model one- and two-digit whole
numbers using a variety of groupings.
