93
Adding mixed numbers (practice)
Textbook: Part 3, lesson 93, pp. 69–71
GoalMore practice adding mixed numbers: three addends, a whole number with a mixed number, perimeter.
New words
addend · qo‘shiluvchisum · yig‘indiside of a triangle · uchburchak tomoniperimeter · perimetr
Explanation
To add several mixed numbers, add all the whole parts together and all the fraction parts together. If the fraction parts give an improper fraction, take the whole out and add it to the total of whole parts. Perimeter is the sum of all side lengths.
Worked examples
3 4/9 + 2 7/9 + 1 5/9 = 6 + 16/9 = 6 + 1 7/9 = 7 7/9.
A triangle has sides 2 3/10 m, 3 5/10 m and 1 9/10 m: perimeter 6 + 17/10 = 7 7/10 m.
Class activity
“Triangle perimeter”: children measure triangle sides in centimetres and millimetres and write lengths as mixed numbers (3 4/10 cm), then add them.
Practice
1
Work out 3 4/9 + 2 7/9 + 1 5/9.
7 7/9
2
Work out 6 + 2 4/5 + 3/5.
9 2/5
3
Compare the sum 4 3/8 + 2 6/8 with 7.
4 3/8 + 2 6/8 > 7
4
On the first day 12 3/10 kg of grapes were picked and on the second day 1 8/10 kg more. How many kilograms were picked in the two days?
26 4/10
5
A triangle has sides 2 3/10 m, 3 5/10 m and 1 9/10 m. Find its perimeter.
7 7/10