63
Rounding up and down (practice)
Textbook: Part 2, lesson 63, pp. 75–77
GoalPractice: rounding up and rounding down.
New words
enough · yetarliwhole · butunshortage · yetishmaslikextra · ortiqcha
Explanation
If a problem says “enough for everyone” we round up; if it says “how many full ... can we make” we round down. Putting 50 rabbits in cages of 6: 50 : 6 = 8 remainder 2, so 8 cages are full (rounding down) and 9 cages are needed for all (rounding up).
Worked examples
7 205: rounded down to thousands 7 000, rounded up 8 000.
Cutting 130 m of ribbon into 25 m pieces gives 5 full pieces; 6 pieces would not be enough ribbon.
Class activity
“Is it enough?”: pick a daily situation (bags, chairs, sweets) and decide whether to round down or up.
Practice
1
Round 7 205 down to the thousands.
7 000
2
Round 7 205 up to the thousands.
8 000
3
130 m of ribbon is cut into 25 m pieces. How many full pieces are there?
5
4
50 rabbits are put 6 to a cage. How many cages are needed for all of them?
9