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HOTS QUESTIONS

1. Fill in the missing digits:

3 4 6 5 3 9 2

– 2 6 – 2 0 1 5 – 2 7 6

9 0 9 2 8 0 1 9

MATHS LAB

Objective: To learn how to subtract the number on an abacus with borrowing.

Things We need: An abacus, beads or different colour

Procedure:

1. Label the sticks of the abacus as Ones, Tens, Hundreds and Thousands
from right to left.

2. Let 1 blue bead represent 1 thousand, 1 yellow bead represent 1 hundred, 1
green bead represent 1 tens and 1 red bead represent 1 ones.

3. Let us subtracted 1257 from 3749.
4. Form the greater number 3749 on the abacus: 3 blue beads for 3 thousands,

7 yellow beads for 7 hundreds, 4 green beads for 4 tens and 9 red beads for 9
ones.

5. First subtract 7 ones of 1257. Remove 7 red beads from 9 red beads leaving

2 red beads. (ones).
6. We can not subtract 5 tens from 4 tens. So we borrow 1 hundred from 7

hundreds (take/yellow bead ) leaving 6 hundreds (6 yellow beads).
Exchange 1 yellow bead for 10 green beads (tens)

Now we have 10 + 4 = 14 green beads
7. Remove 5 green beads from 14 green beads leaving 9 green beads (tens).

8. To subtract 2 hundreds from 6 hundreds, remove 2 yellow beads leaving 4
yellow beads (hundreds).

9. To subtract thousands remove 1 blue beads leaving 2 blue beads
(thousands).

10. Count different beads on the sticks. The number formed by these beads in 2492.

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Subtraction
Mathematics-3