98
Subtracting with regrouping (practice)
Textbook: Part 3, lesson 98, pp. 84–86
GoalMore practice subtracting with regrouping: expressions with brackets, word problems.
New words
subtracting with regrouping · birlikdan o‘tib ayirishbracket · qavsexpression · ifodaleft · qolgan
Explanation
If the fraction part of the minuend is smaller than that of the subtrahend, take one unit from the whole part, change it into shares and add it to the fraction part. In expressions with brackets, work out the brackets first. You can check the result by adding.
Worked examples
7 1/8 − 2 5/8 = 6 9/8 − 2 5/8 = 4 4/8.
12 − (3 4/10 + 2 5/10) = 12 − 5 9/10 = 11 10/10 − 5 9/10 = 6 1/10.
Class activity
“Find the mistake”: the teacher writes a subtraction with regrouping that contains a mistake. Children find it, write the correct solution and check by adding.
Practice
1
Work out 7 1/8 − 2 5/8.
4 4/8
2
Work out (6 2/9 + 1 3/9) − 3 5/9.
4
3
Work out 12 − (3 4/10 + 2 5/10).
6 1/10
4
3 5/6 m of an 8 m cable was used. How many metres are left?
4 1/6
5
Bobur covered a 5 1/5 km route: 2 3/5 km on foot and the rest by bicycle. How many kilometres did he cycle?
2 3/5