Chirag and Nandini love spending their vacation with their Nani Maa, playing games, and learning new mathematical concepts through fun activities.
Nani Maa shows a magic trick where she can guess the number of hidden marbles or seeds under a handkerchief by knowing the total number and the number of visible seeds.
The mathematical rule behind this trick is:
$$\text{Total Seeds} = \text{Seeds on the Table} + \text{Hidden Seeds}$$
$$\text{Hidden Seeds} = \text{Total Seeds} - \text{Seeds on the Table}$$
The tens frame is a visual tool that helps children group numbers into tens and ones to make addition and subtraction easier.
Nandini has $7$ balushahis and Chirag has $5$ balushahis.
Chirag got $9$ story books and Nandini got $7$ puzzle books. To find the total books:
$$9 + 7 = 16 \text{ books}$$
A ginladi (bead string) or number line helps visualize addition and subtraction as forward and backward jumps.
Nandini and Chirag have $15$ stamps. Nani Maa gives them $7$ more. Total stamps = $15 + 7 = 22$.
Three different ways to jump on the ginladi:
They have $52$ stamps in total. $37$ have faces of famous persons, and the rest have pictures of monuments.
$$52 - 37 = 15 \text{ monument stamps}$$
Number Line Strategy: Start at $52$, jump backward $-2$ to $50$, then $-10$ to $40$, then $-3$ to $37$. Total backward jump = $2 + 10 + 3 = 15$.
A number grid from $1$ to $100$ allows quick addition and subtraction by jumping vertically (by tens) and horizontally (by ones).
A magic square is a grid of numbers where the sum of numbers in each row, column, and diagonal is equal.
Using numbers $1$ to $9$ exactly once, the magic sum is $15$:
| $8$ | $3$ | $4$ |
| $1$ | $5$ | $9$ |
| $6$ | $7$ | $2$ |