counting on and back y3

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Transcript counting on and back y3

Look at these sequences.
What is happening?
1, 2, 3, 4, 5, 6, 7, 8, 9, 10
10, 20, 30, 40, 50, 60, 70, 80, 90,100
100, 200, 300, 400, 500, 600, 700, 800, 900, 1000
Counting on in tens.
Counting on in tens means adding ten on
to the previous number in the sequence.
Practice:
10, 20, 30, …, …, …, …, …, …, …, …,
Now try starting at 100
100, 110, …., ….., ….., ….., …..,
Counting back in tens.
Counting back in tens means taking ten away
from the previous number in the sequence.
Try it:
100, 90, ….., ….., ….., …..,
Now try to complete this sequence. Can you fill
in the gaps?
120, ….., 100, ……, ……, 70
Counting on and back in
hundreds.
Counting on and back in hundreds is similar to
the tens but this time you use hundreds
instead.
Counting on:
100, 200, 300, 400, 500
Counting back:
500, 400, 300, 200, 100
Look carefully at this
sequence!
What changes in this sequence?
256, 356, 456, 556, 656, 756, 856, 956
What stays the same?
Look at these sequences.
Discuss with your friend what is
happening in each one.
5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15
122, 132, 142, 152, 162, 172, 182
421, 521, 621, 721, 821, 921, 1021