95
Completing problems with missing data
Textbook Part 3, pp. 44–45
GoalSpot what is missing in a text and complete it to make a solvable problem.
New words
missing · yetishmayotganinformation · ma’lumotto complete · to‘ldirmoq
Explanation
To solve a problem we need enough information. “A class has 15 pupils and some teachers. How many people?” — the number of teachers is missing, so it cannot be solved. When we add the missing number, it becomes a real problem.
Worked examples
“An album has 15 black-and-white and 55 colour photos.” Add a question: “How many in all?” → 15 + 55 = 70.
“A bus had 30 people. Some got off at a stop. How many are left?” — we are missing how many got off.
Class activity
“Missing-number detective”: the teacher reads incomplete problems. Children say what is missing, then fill in their own numbers and solve.
Practice
1
“The orchard has 24 apple trees. How many trees in all?” What is missing?
The number of other trees
2
Add a question and solve: “A sack had 38 kg of flour; 15 kg was used.”
How much is left? 38 − 15 = 23 kg
3
Write and solve: 3 tens 1 one + 5 tens 6 ones
31 + 56 = 87
4
What does a cylinder look like from above?
A circle