Estimating Answers by Rounding
Which is the best estimate for 49 × 21? Momo the monkey rounds each number to something friendly (50 × 20) to get about 1,000 in seconds. Learn to estimate before you calculate and to use an estimate to catch mistakes, then estimate 398 + 203 yourself.
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1:59Order of Operations (BIDMAS)
Fizz the fox thinks 3 + 4 × 2 is 14, but Professor Hoot the owl shows why it is 11. Learn BIDMAS (brackets, indices, divide and multiply, add and subtract), then try (10 − 4) × 3 and see why equal partners go left to right.
2:19Column Addition and Subtraction: Carrying and Exchanging
Bruno the bear adds 476 + 358 in columns, starting with the ones and carrying when a column makes ten or more (834). Then learn exchanging for subtraction with 62 − 27, and try 503 − 168 yourself, where you have to exchange across a zero.
1:48Long Multiplication: Multiplying by a 2-Digit Number
Leo the lion works out 34 × 26 with the column method: multiply by the 6 ones (204), then by the 2 tens with a zero placeholder (680), then add the two parts to get 884. Then try 23 × 15 yourself and learn why the placeholder zero matters.