3
Taking away and comparing
Discover Mathematics: Chapter 6
GoalTake away within 10 by crossing out, and find how many more one group has than another.
New words
take away · some go awayleft · what stays after some godifference · how many more or fewermatch · put one thing with one thing
Explanation
Taking away means a group gets smaller. Cross out the things that go away and count what is left. Here are 7 birds. 3 fly away, so we cross out 3. Four birds are left. We write 7 − 3 = 4. To find how many more one group has, match each thing in one group with a thing in the other. The things with no partner show the difference.
Worked examples
Yassin has 8 oranges. He gives 2 away. 8 − 2 = 6, so 6 oranges are left.
Lina has 6 balloons. 4 pop. 6 − 4 = 2, so 2 balloons are left.
There are 7 cats and 4 dogs. Match each dog with a cat. 3 cats have no partner, so there are 3 more cats than dogs.
Class activity
Spoons and cups. Put 7 spoons in one row and 4 cups in a row below. Match each cup with a spoon and count the spoons with no cup. Then take 2 spoons away and say how many are left. Swap the numbers and play again.
Practice
1
What is 5 − 2? Count what is not crossed out.
3
2
Reem has 9 dates. She eats 4. How many dates are left?
5
3
How many more apples than pears are there?
2 more apples
4
What is 10 − 3?
7
5
There are 4 goats in the field. All 4 walk away. How many goats are left?
0