Typed-Answer Drills 1: Numbers, Money and Units

Two or three typed items are plain arithmetic, and they are the fastest marks on the paper — so don't rush them into an error. Four thousand three hundred and fifty-six plus two thousand seven hundred is seven thousand and fifty-six. For a decimal subtraction write the missing zero first, so eight point four becomes eight point four zero, and take away two point six five to get five point seven five. Estimate before you write: about seven thousand one hundred, so seven thousand and fifty-six is believable.

Money questions go wrong when the two units get mixed in one sum. Pick one — cents while the numbers are small — and convert once at the end. Three pencils at forty-five cents and a rubber at sixty-five is two hundred cents, and if that equals two pens, a pen is a hundred cents, a dollar. Five dollars less three eighty-five-cent pens is five hundred take two hundred and fifty-five, two hundred and forty-five cents, two dollars forty-five. Remember the decimal point moves two places, not one.

For a rate, go through one. Fifteen dollars buys three toy cars, so one car is five dollars, and forty-five dollars buys nine. You can also notice that forty-five is three times fifteen, so it buys three times as many — nine again. Then check the direction, because more money must buy more: if the answer came out smaller than three, the division went the wrong way round. The same method handles kilometres per litre and words per minute.

Two shapes come up nearly every year. First, rounding in context: fifty-eight pencils eight to a packet is seven remainder two, so eight packets hold them all, seven packets are full, and two are left over — one division, three answers. Second, digit cards. For the largest number put the biggest digit first, which for three, six and eight gives eight hundred and sixty-three — but that is odd. For the largest even number, fix the ones place first with an even digit, and use the smaller even one so the bigger digits stay at the front: eight hundred and thirty-six.

Several typed items are nothing but a careful count from a picture — dots inside overlapping shapes, cubes in a stack, shaded squares. There is no arithmetic to get wrong, only the counting, so always count in a fixed order, left to right and then the next row, and mark each one as you go. A three by four grid with five shaded leaves seven unshaded, and multiplying to check the total catches a miscount. Count it twice. Quiz and exercises now.