Part of Maths and NumeracyNumbers and number processes
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Snoot and Fin use compensation to make adding and subtracting two digit numbers easier.
NARRATOR: Hello Snoot. Hello Fin.
Hello cousin Plimble.
PLIMBLE: Plimble!
NARRATOR: What鈥檚 going on?
SNOOT: (ALIEN LANGUAGE)
NARRATOR: You鈥檙e doing time trials with your racing meebs.
That looks fun.
How many meebs are in the race?
NARRATOR: I see.
24 meebs started the race, but 9 have dropped out.
How many meebs does that leave on the track?
SNOOT: Er鈥 Uh鈥
NARRATOR: Let鈥檚 see.
Taking away 9 can be a bit tricky, but 9 is only 1 away from 10, so let鈥檚 take 10 away instead.
24 take away 10 is 14.
Then we have to put 1 back, because we took away 10, but we only wanted to take away 9.
14 add 1 equals 15, so 24 take away 9 leaves 15 meebs still in the race.
ALL: Aha!
NARRATOR: Oh look, 2 more meebs have just given up, which means 11 have dropped out from the 24 that started.
How many meebs are in the race now?
FIN: (ALIEN LANGUAGE)
NARRATOR: That鈥檚 right Fin.
You can work it out by taking away 10 again, because 11 is only 1 away from 10.
Then we have to take away another 1, because we wanted to take away 11, not just 10.
14 take away 1 equals 13, so 24 take away 11 leaves 13 meebs still in the race.
Which meeb are you supporting, Snoot?
(ALIEN LANGUAGE)
NARRATOR: The red one; come on red!
(BOING)
NARRATOR: Ah鈥
Another meeb bites the dust.
Everyone finds some numbers easier to work with than others. You might find adding or taking away 10 is easier than 9 or 11.
Compensation is a way of adding or taking away numbers that you find easier.
You add or take away a bit too much or a bit too little, so then you have to add or take away this too.
26 - 9 = ?
Try taking away 10 instead.
26 - 10 = 16
You have taken away 1 too many (10 is 1 more than 9)
So add the 1 back on
16 + 1 = 17
It works for adding too
33 + 12 = ?
Try adding 10 instead.
33 + 10 = 43
You need to add on 2 more (10 is 2 less than 12)
43 + 2 = 45
Fin and Snoot add up some of their favourite snacks: space grubs and astro bugs.
Snoot and Fin rearrange numbers and make number bonds when adding moons.
Find more 1st Level resources from 91热爆 Bitesize
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