Abacus

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Transcript

00:00In today's class, we will study the topic, Representation of Numbers on a Spike Abacus.

00:11An abacus is an instrument that can be used for counting and knowing the place value of

00:21each digit in a number.

00:25An abacus has spikes depending on the number of digits in a number.

00:33The digits are represented using beads.

00:38To count or represent a two digit number, we used a two spike abacus.

00:48To count or show a three digit number, we used a three spike abacus.

00:57Children, let's look at this three spikes abacus representing 100s, 10s and 1s place.

01:09Now we find the number shown on the given abacus.

01:14Let's count the number of beads on each spike.

01:19100s place consists of 3 beads, 10s place has 7 beads and 1s place shows 4 beads.

01:33So the number represented here is 374.

01:44As we move on, let's represent the number 463 on a spike abacus.

01:53We know that 463 is equal to 4 100s plus 6 10s plus 3 1s.

02:06So we put 4 beads in 100s spike to show 4 100s, we put 6 beads in 10s spike to show

02:196 10s and put 3 beads in the 1s spike to show 3 1s.

02:37Let's take another example, represent the number 520 on a spike abacus.

02:47We know that 520 is equal to 5 100s plus 2 10s plus 0 1s.

03:00So we put 5 beads in the 100s spike to show 5 100s, put 2 beads in the 10s spike to show

03:132 10s, here leave the 1s spike empty as there are 0 1s in the number.

03:27Dear students, let's get started for a space work activity assigned in the following slide

03:36to be done in a drawing sheet.