Numbers in many forms

In your book, Maths Mela (Chapter 4), Jaspreet and Gulnaz are organising a langar, a community lunch, at the Gurudwara in their neighbourhood. They expect about one thousand people! Many people send donations, and each amount is written in a different way. Let us find each number.

The rice is shown as 3 tens and 9 ones. 3 tens is 30, and 30 + 9 = 39. The wheat flour is written '4 Ones + 7 Tens'. Be careful: the ones come first here, but 7 tens is 70 and 4 ones is 4, so the number is 74, not 47. The pulses are 10 bundles of ten sticks and 3 loose sticks. 10 tens make 100, so that is 100 + 3 = 103.

The pumpkins are written '100 − 7'. Count back 7 from 100: 99, 98, 97, 96, 95, 94, 93. So there are 93 pumpkins. The salt is '10 + 10 + 10 + 10 + 10': five tens, which is 50. The plates are 4 hundreds, 8 tens and 2 ones: 400 + 80 + 2 = 482.

The sugar is the number halfway between 60 and 70. Halfway means the same distance from both: 65 is 5 more than 60 and 5 less than 70. The cups are 'ten more than three hundred twelve'. Ten more than 312 changes only the tens digit: 312 becomes 322.

The same number can be shown in many ways: as blocks, bundles, a sum, a take-away, or words. Always ask how many hundreds, tens and ones there are.