Rules
(1) When subtracting larger whole number starts from the one’s column and move to the left.
(2) We cannot subtract from the column we are on therefore, we borrow from the column to the left but the number in the left is 0 then we borrow from the next two places to the left.
Example:- 900 – 738
Procedure:
(1) We cannot subtract 0 – 8, in the one’s column therefore, we have to borrow one group from the ten’s column but if tenth column has also 0 then we must borrow ten’s and hundred’s column together combined (90)
(2) We have now only 89, left in the ten’s and hundred’s column and add the group of ten we borrow to the one’s column and now making it ten then
10 – 8 = 2 (one’s column)
9 – 3 = 6 (ten’s column)
8 – 7 = 1( hundred’s column) = 162.
Problem
Problem:-
100 700 800 600
-55 -157 -567 -114
___ ____ ____ ____
500 400 300 900
-123 -197 -267 -714
____ ____ ____ ____
How to Solve the Word Problem
Word problem
Example 1.In a school there 900 students. If there were 756 boys , find the number of girls in the school.
Solution: Total number of students in the school = 900
Number of boys in the school = – 756
Number of girls in the school = 144
Procedure
1). We cannot subtract 0 – 6, in the one’s column therefore, we have to borrow one group from the ten’s column but if tenth column has also 0 then we must borrow ten’sand hundred’s column together combined (90)
2).We have now 89,left in the ten’s and hundred’s column and the add the group of ten we borrow to the one’s column and now making it ten then
10 – 6 = 4 (one’s column)
9 – 5 = 4 (ten’s column)
8 – 7 = 1(hundred’s column) = 144
Example 2.There are 400 flower plants in a garden. Out of them, 238 are marigold plants and the remaining are rose plants. How many rose plants are there?
Solution: Total number of plants = 400
Number of marigold plants = – 238
Number of rose plants = 162
Procedure
1). We cannot subtract 0 – 8, in the one’s column therefore, we have to borrow one group from the ten’s column but if tenth column has also 0 then we must borrow ten’sand hundred’s column together combined (90)
2).We have now 89,left in the ten’s and hundred’s column and the add the group of ten we borrow to the one’s column and now making it ten then
10 – 8 = 4 (one’s column)
9 – 3 = 4 (ten’s column)
3 – 2 = 1(hundred’s column) = 162
Example 3. In a health camp, the doctors attended 700 patients. If there were 234 male patients, find the number of female patient.
Solution: Number of patients = 700
Number male patients = – 234
Number of female patients = 466
Procedure
1). We cannot subtract 0 – 4, in the one’s column therefore, we have to borrow one group from the ten’s column but if tenth column has also 0 then we must borrow ten’sand hundred’s column together combined (90)
2).We have now 89,left in the ten’s and hundred’s column and the add the group of ten we borrow to the one’s column and now making it ten then
10 – 4 = 4 (one’s column)
9 – 3 = 4 (ten’s column)
6 – 2 = 1(hundred’s column) = 466
Example 4.David had 200 toys and Emily had 98 toys. Calculate the difference?
Solution: David had toys = 200
Emily had toys = - 98
Difference of toys = 102
Procedure
1). We cannot subtract 0 – 8, in the one’s column therefore, we have to borrow one group from the ten’s column but if tenth column has also 0 then we must borrow ten’sand hundred’s column together combined (90)
2).We have now 89,left in the ten’s and hundred’s column and the add the group of ten we borrow to the one’s column and now making it ten then
10 – 8 = 2 (one’s column)
9 – 9 = 0 (ten’s column)
1 – 0 = 1(hundred’s column) = 102