Quick Notes

Quick Notes

Mathematics Chapter 2: Basic Operations
2.2 Add within 100
2.2  Add within 100

There are various methods to solve suitable addition operations for numbers up to 100

  • The method says it all
  • Using an abacus
  • Using common forms
 
Examples of questions and solutions to addition operations

Siti has 6 marbles. Amir gave him 2 more marbles. How many marbles does Siti have?

Mathematical sentences: \(6 +2= 8\)
Count all 

Count all of the numbers and list it such as:

 1,2,3,4,5,6,7,8 

The total number of marbles that Siti has is 8.
Using abacus

The picture (left) shows the arrangement of the abacus for number 6.

2 abacus are brought up as an addition operation.

The result is like the picture (right), the abacus shows the arrangement of 8.

  

 
Using long method

 

We solve this addition problem by adding the number that is, which we will get.

Then, if there are numbers on the left, continue adding as before.

We write the answer as below.

\(\begin {array}{rr} \space\space6\\+\quad\space\space2\\\hline \space\space8 \\\hline \end {array} \)